diff --git a/cmds/statsd/src/guardrail/StatsdStats.cpp b/cmds/statsd/src/guardrail/StatsdStats.cpp
index c4034ff..06a5bd9 100644
--- a/cmds/statsd/src/guardrail/StatsdStats.cpp
+++ b/cmds/statsd/src/guardrail/StatsdStats.cpp
@@ -448,6 +448,11 @@
     getAtomMetricStats(metricId).bucketDropped++;
 }
 
+void StatsdStats::noteBucketUnknownCondition(int64_t metricId) {
+    lock_guard<std::mutex> lock(mLock);
+    getAtomMetricStats(metricId).bucketUnknownCondition++;
+}
+
 void StatsdStats::noteConditionChangeInNextBucket(int64_t metricId) {
     lock_guard<std::mutex> lock(mLock);
     getAtomMetricStats(metricId).conditionChangeInNextBucket++;
diff --git a/cmds/statsd/src/guardrail/StatsdStats.h b/cmds/statsd/src/guardrail/StatsdStats.h
index ea3f3b3..1de46b8 100644
--- a/cmds/statsd/src/guardrail/StatsdStats.h
+++ b/cmds/statsd/src/guardrail/StatsdStats.h
@@ -381,6 +381,11 @@
     void noteBucketBoundaryDelayNs(int64_t metricId, int64_t timeDelayNs);
 
     /**
+     * Number of buckets with unknown condition.
+     */
+    void noteBucketUnknownCondition(int64_t metricId);
+
+    /**
      * Reset the historical stats. Including all stats in icebox, and the tracked stats about
      * metrics, matchers, and atoms. The active configs will be kept and StatsdStats will continue
      * to collect stats after reset() has been called.
@@ -428,6 +433,7 @@
         long bucketDropped = 0;
         int64_t minBucketBoundaryDelayNs = 0;
         int64_t maxBucketBoundaryDelayNs = 0;
+        long bucketUnknownCondition = 0;
     } AtomMetricStats;
 
 private:
diff --git a/cmds/statsd/src/metrics/CountMetricProducer.cpp b/cmds/statsd/src/metrics/CountMetricProducer.cpp
index 350745b..5707de5 100644
--- a/cmds/statsd/src/metrics/CountMetricProducer.cpp
+++ b/cmds/statsd/src/metrics/CountMetricProducer.cpp
@@ -250,7 +250,7 @@
 void CountMetricProducer::onConditionChangedLocked(const bool conditionMet,
                                                    const int64_t eventTime) {
     VLOG("Metric %lld onConditionChanged", (long long)mMetricId);
-    mCondition = conditionMet;
+    mCondition = conditionMet ? ConditionState::kTrue : ConditionState::kFalse;
 }
 
 bool CountMetricProducer::hitGuardRailLocked(const MetricDimensionKey& newKey) {
diff --git a/cmds/statsd/src/metrics/DurationMetricProducer.cpp b/cmds/statsd/src/metrics/DurationMetricProducer.cpp
index 6c1c47b..da6b97c 100644
--- a/cmds/statsd/src/metrics/DurationMetricProducer.cpp
+++ b/cmds/statsd/src/metrics/DurationMetricProducer.cpp
@@ -433,7 +433,7 @@
 void DurationMetricProducer::onConditionChangedLocked(const bool conditionMet,
                                                       const int64_t eventTime) {
     VLOG("Metric %lld onConditionChanged", (long long)mMetricId);
-    mCondition = conditionMet;
+    mCondition = conditionMet ? ConditionState::kTrue : ConditionState::kFalse;
     flushIfNeededLocked(eventTime);
     for (auto& whatIt : mCurrentSlicedDurationTrackerMap) {
         for (auto& pair : whatIt.second) {
@@ -767,12 +767,13 @@
                            !mSameConditionDimensionsInTracker,
                            !mHasLinksToAllConditionDimensionsInTracker,
                            &dimensionKeysInCondition);
-        condition = (conditionState == ConditionState::kTrue);
+        condition = conditionState == ConditionState::kTrue;
         if (mDimensionsInCondition.empty() && condition) {
             dimensionKeysInCondition.insert(DEFAULT_DIMENSION_KEY);
         }
     } else {
-        condition = mCondition;
+        // TODO: The unknown condition state is not handled here, we should fix it.
+        condition = mCondition == ConditionState::kTrue;
         if (condition) {
             dimensionKeysInCondition.insert(DEFAULT_DIMENSION_KEY);
         }
diff --git a/cmds/statsd/src/metrics/DurationMetricProducer.h b/cmds/statsd/src/metrics/DurationMetricProducer.h
index 1b830a3..ec561b5 100644
--- a/cmds/statsd/src/metrics/DurationMetricProducer.h
+++ b/cmds/statsd/src/metrics/DurationMetricProducer.h
@@ -137,6 +137,7 @@
 
     FRIEND_TEST(DurationMetricTrackerTest, TestNoCondition);
     FRIEND_TEST(DurationMetricTrackerTest, TestNonSlicedCondition);
+    FRIEND_TEST(DurationMetricTrackerTest, TestNonSlicedConditionUnknownState);
     FRIEND_TEST(DurationMetricTrackerTest, TestSumDurationWithUpgrade);
     FRIEND_TEST(DurationMetricTrackerTest, TestSumDurationWithUpgradeInFollowingBucket);
     FRIEND_TEST(DurationMetricTrackerTest, TestMaxDurationWithUpgrade);
diff --git a/cmds/statsd/src/metrics/EventMetricProducer.cpp b/cmds/statsd/src/metrics/EventMetricProducer.cpp
index 7e695a6..3b4af65 100644
--- a/cmds/statsd/src/metrics/EventMetricProducer.cpp
+++ b/cmds/statsd/src/metrics/EventMetricProducer.cpp
@@ -132,7 +132,7 @@
 void EventMetricProducer::onConditionChangedLocked(const bool conditionMet,
                                                    const int64_t eventTime) {
     VLOG("Metric %lld onConditionChanged", (long long)mMetricId);
-    mCondition = conditionMet;
+    mCondition = conditionMet ? ConditionState::kTrue : ConditionState::kFalse;
 }
 
 void EventMetricProducer::onMatchedLogEventInternalLocked(
diff --git a/cmds/statsd/src/metrics/GaugeMetricProducer.cpp b/cmds/statsd/src/metrics/GaugeMetricProducer.cpp
index d56a355..837d532 100644
--- a/cmds/statsd/src/metrics/GaugeMetricProducer.cpp
+++ b/cmds/statsd/src/metrics/GaugeMetricProducer.cpp
@@ -320,15 +320,15 @@
         // When the metric wants to do random sampling and there is already one gauge atom for the
         // current bucket, do not do it again.
         case GaugeMetric::RANDOM_ONE_SAMPLE: {
-            triggerPuller = mCondition && mCurrentSlicedBucket->empty();
+            triggerPuller = mCondition == ConditionState::kTrue && mCurrentSlicedBucket->empty();
             break;
         }
         case GaugeMetric::CONDITION_CHANGE_TO_TRUE: {
-            triggerPuller = mCondition;
+            triggerPuller = mCondition == ConditionState::kTrue;
             break;
         }
         case GaugeMetric::FIRST_N_SAMPLES: {
-            triggerPuller = mCondition;
+            triggerPuller = mCondition == ConditionState::kTrue;
             break;
         }
         default:
@@ -364,7 +364,7 @@
                                                    const int64_t eventTimeNs) {
     VLOG("GaugeMetric %lld onConditionChanged", (long long)mMetricId);
     flushIfNeededLocked(eventTimeNs);
-    mCondition = conditionMet;
+    mCondition = conditionMet ? ConditionState::kTrue : ConditionState::kFalse;
     if (mIsPulled && mTriggerAtomId == -1) {
         pullAndMatchEventsLocked(eventTimeNs);
     }  // else: Push mode. No need to proactively pull the gauge data.
@@ -377,7 +377,7 @@
     flushIfNeededLocked(eventTimeNs);
     // If the condition is sliced, mCondition is true if any of the dimensions is true. And we will
     // pull for every dimension.
-    mCondition = overallCondition;
+    mCondition = overallCondition ? ConditionState::kTrue : ConditionState::kFalse;
     if (mIsPulled && mTriggerAtomId == -1) {
         pullAndMatchEventsLocked(eventTimeNs);
     }  // else: Push mode. No need to proactively pull the gauge data.
diff --git a/cmds/statsd/src/metrics/MetricProducer.cpp b/cmds/statsd/src/metrics/MetricProducer.cpp
index 495138e..423d050 100644
--- a/cmds/statsd/src/metrics/MetricProducer.cpp
+++ b/cmds/statsd/src/metrics/MetricProducer.cpp
@@ -45,7 +45,8 @@
                            &dimensionKeysInCondition);
         condition = (conditionState == ConditionState::kTrue);
     } else {
-        condition = mCondition;
+        // TODO: The unknown condition state is not handled here, we should fix it.
+        condition = mCondition == ConditionState::kTrue;
     }
 
     if (mDimensionsInCondition.empty() && condition) {
diff --git a/cmds/statsd/src/metrics/MetricProducer.h b/cmds/statsd/src/metrics/MetricProducer.h
index 849cb76..8ab3b06 100644
--- a/cmds/statsd/src/metrics/MetricProducer.h
+++ b/cmds/statsd/src/metrics/MetricProducer.h
@@ -59,7 +59,7 @@
           mTimeBaseNs(timeBaseNs),
           mCurrentBucketStartTimeNs(timeBaseNs),
           mCurrentBucketNum(0),
-          mCondition(conditionIndex >= 0 ? false : true),
+          mCondition(conditionIndex >= 0 ? ConditionState::kUnknown : ConditionState::kTrue),
           mConditionSliced(false),
           mWizard(wizard),
           mConditionTrackerIndex(conditionIndex),
@@ -315,7 +315,7 @@
 
     int64_t mBucketSizeNs;
 
-    bool mCondition;
+    ConditionState mCondition;
 
     bool mConditionSliced;
 
diff --git a/cmds/statsd/src/metrics/ValueMetricProducer.cpp b/cmds/statsd/src/metrics/ValueMetricProducer.cpp
index 851ae99..bc7c872 100644
--- a/cmds/statsd/src/metrics/ValueMetricProducer.cpp
+++ b/cmds/statsd/src/metrics/ValueMetricProducer.cpp
@@ -154,7 +154,7 @@
     // Adjust start for partial bucket
     mCurrentBucketStartTimeNs = startTimeNs;
     // Kicks off the puller immediately if condition is true and diff based.
-    if (mIsPulled && mCondition && mUseDiff) {
+    if (mIsPulled && mCondition == ConditionState::kTrue && mUseDiff) {
         pullAndMatchEventsLocked(startTimeNs);
     }
     VLOG("value metric %lld created. bucket size %lld start_time: %lld", (long long)metric.id(),
@@ -341,17 +341,21 @@
     flushIfNeededLocked(eventTimeNs);
 
     // Pull on condition changes.
-    if (mIsPulled && (mCondition != condition)) {
+    bool conditionChanged = mCondition != condition;
+    bool unknownToFalse = mCondition == ConditionState::kUnknown
+            && condition == ConditionState::kFalse;
+    // We do not need to pull when we go from unknown to false.
+    if (mIsPulled && conditionChanged && !unknownToFalse) {
         pullAndMatchEventsLocked(eventTimeNs);
     }
 
     // when condition change from true to false, clear diff base but don't
     // reset other counters as we may accumulate more value in the bucket.
-    if (mUseDiff && mCondition && !condition) {
+    if (mUseDiff && mCondition == ConditionState::kTrue && condition == ConditionState::kFalse) {
         resetBase();
     }
 
-    mCondition = condition;
+    mCondition = condition ? ConditionState::kTrue : ConditionState::kFalse;
 }
 
 void ValueMetricProducer::pullAndMatchEventsLocked(const int64_t timestampNs) {
@@ -372,7 +376,7 @@
 void ValueMetricProducer::onDataPulled(const std::vector<std::shared_ptr<LogEvent>>& allData,
                                        bool pullSuccess, int64_t originalPullTimeNs) {
     std::lock_guard<std::mutex> lock(mMutex);
-    if (mCondition) {
+    if (mCondition == ConditionState::kTrue) {
         if (!pullSuccess) {
             // If the pull failed, we won't be able to compute a diff.
             invalidateCurrentBucket();
@@ -725,6 +729,10 @@
 }
 
 void ValueMetricProducer::flushCurrentBucketLocked(const int64_t& eventTimeNs) {
+    if (mCondition == ConditionState::kUnknown) {
+        StatsdStats::getInstance().noteBucketUnknownCondition(mMetricId);
+    }
+
     VLOG("finalizing bucket for %ld, dumping %d slices", (long)mCurrentBucketStartTimeNs,
          (int)mCurrentSlicedBucket.size());
     int64_t fullBucketEndTimeNs = getCurrentBucketEndTimeNs();
diff --git a/cmds/statsd/src/stats_log.proto b/cmds/statsd/src/stats_log.proto
index 6a07a3f..7a3ba7f 100644
--- a/cmds/statsd/src/stats_log.proto
+++ b/cmds/statsd/src/stats_log.proto
@@ -421,6 +421,7 @@
       optional int64 bucket_dropped = 8;
       optional int64 min_bucket_boundary_delay_ns = 9;
       optional int64 max_bucket_boundary_delay_ns = 10;
+      optional int64 bucket_unknown_condition = 11;
     }
     repeated AtomMetricStats atom_metric_stats = 17;
 
diff --git a/cmds/statsd/src/stats_log_util.cpp b/cmds/statsd/src/stats_log_util.cpp
index aa8cfc5..ed6eb4b 100644
--- a/cmds/statsd/src/stats_log_util.cpp
+++ b/cmds/statsd/src/stats_log_util.cpp
@@ -82,6 +82,7 @@
 const int FIELD_ID_BUCKET_DROPPED = 8;
 const int FIELD_ID_MIN_BUCKET_BOUNDARY_DELAY_NS = 9;
 const int FIELD_ID_MAX_BUCKET_BOUNDARY_DELAY_NS = 10;
+const int FIELD_ID_BUCKET_UNKNOWN_CONDITION = 11;
 
 namespace {
 
@@ -506,6 +507,8 @@
                        (long long)pair.second.minBucketBoundaryDelayNs);
     protoOutput->write(FIELD_TYPE_INT64 | FIELD_ID_MAX_BUCKET_BOUNDARY_DELAY_NS,
                        (long long)pair.second.maxBucketBoundaryDelayNs);
+    protoOutput->write(FIELD_TYPE_INT64 | FIELD_ID_BUCKET_UNKNOWN_CONDITION,
+                       (long long)pair.second.bucketUnknownCondition);
     protoOutput->end(token);
 }
 
diff --git a/cmds/statsd/tests/metrics/DurationMetricProducer_test.cpp b/cmds/statsd/tests/metrics/DurationMetricProducer_test.cpp
index b540964..b294cad 100644
--- a/cmds/statsd/tests/metrics/DurationMetricProducer_test.cpp
+++ b/cmds/statsd/tests/metrics/DurationMetricProducer_test.cpp
@@ -117,6 +117,7 @@
     DurationMetricProducer durationProducer(
             kConfigKey, metric, 0 /* condition index */, 1 /* start index */, 2 /* stop index */,
             3 /* stop_all index */, false /*nesting*/, wizard, dimensions, bucketStartTimeNs, bucketStartTimeNs);
+    durationProducer.mCondition = ConditionState::kFalse;
 
     EXPECT_FALSE(durationProducer.mCondition);
     EXPECT_FALSE(durationProducer.isConditionSliced());
@@ -140,6 +141,51 @@
     EXPECT_EQ(1LL, buckets2[0].mDuration);
 }
 
+TEST(DurationMetricTrackerTest, TestNonSlicedConditionUnknownState) {
+    sp<MockConditionWizard> wizard = new NaggyMock<MockConditionWizard>();
+    int64_t bucketStartTimeNs = 10000000000;
+    int64_t bucketSizeNs = TimeUnitToBucketSizeInMillis(ONE_MINUTE) * 1000000LL;
+
+    DurationMetric metric;
+    metric.set_id(1);
+    metric.set_bucket(ONE_MINUTE);
+    metric.set_aggregation_type(DurationMetric_AggregationType_SUM);
+
+    int tagId = 1;
+    LogEvent event1(tagId, bucketStartTimeNs + 1);
+    event1.init();
+    LogEvent event2(tagId, bucketStartTimeNs + 2);
+    event2.init();
+    LogEvent event3(tagId, bucketStartTimeNs + bucketSizeNs + 1);
+    event3.init();
+    LogEvent event4(tagId, bucketStartTimeNs + bucketSizeNs + 3);
+    event4.init();
+
+    FieldMatcher dimensions;
+    DurationMetricProducer durationProducer(
+            kConfigKey, metric, 0 /* condition index */, 1 /* start index */, 2 /* stop index */,
+            3 /* stop_all index */, false /*nesting*/, wizard, dimensions, bucketStartTimeNs, bucketStartTimeNs);
+
+    EXPECT_EQ(ConditionState::kUnknown, durationProducer.mCondition);
+    EXPECT_FALSE(durationProducer.isConditionSliced());
+
+    durationProducer.onMatchedLogEvent(1 /* start index*/, event1);
+    durationProducer.onMatchedLogEvent(2 /* stop index*/, event2);
+    durationProducer.flushIfNeededLocked(bucketStartTimeNs + bucketSizeNs + 1);
+    EXPECT_EQ(0UL, durationProducer.mPastBuckets.size());
+
+    durationProducer.onMatchedLogEvent(1 /* start index*/, event3);
+    durationProducer.onConditionChanged(true /* condition */, bucketStartTimeNs + bucketSizeNs + 2);
+    durationProducer.onMatchedLogEvent(2 /* stop index*/, event4);
+    durationProducer.flushIfNeededLocked(bucketStartTimeNs + 2 * bucketSizeNs + 1);
+    EXPECT_EQ(1UL, durationProducer.mPastBuckets.size());
+    const auto& buckets2 = durationProducer.mPastBuckets[DEFAULT_METRIC_DIMENSION_KEY];
+    EXPECT_EQ(1UL, buckets2.size());
+    EXPECT_EQ(bucketStartTimeNs + bucketSizeNs, buckets2[0].mBucketStartNs);
+    EXPECT_EQ(bucketStartTimeNs + 2 * bucketSizeNs, buckets2[0].mBucketEndNs);
+    EXPECT_EQ(1LL, buckets2[0].mDuration);
+}
+
 TEST(DurationMetricTrackerTest, TestSumDurationWithUpgrade) {
     /**
      * The duration starts from the first bucket, through the two partial buckets (10-70sec),
diff --git a/cmds/statsd/tests/metrics/ValueMetricProducer_test.cpp b/cmds/statsd/tests/metrics/ValueMetricProducer_test.cpp
index 572b199..7e7ffed 100644
--- a/cmds/statsd/tests/metrics/ValueMetricProducer_test.cpp
+++ b/cmds/statsd/tests/metrics/ValueMetricProducer_test.cpp
@@ -2176,7 +2176,7 @@
                                       eventMatcherWizard, tagId, bucketStartTimeNs,
                                       bucketStartTimeNs, pullerManager);
 
-    valueProducer.mCondition = true;
+    valueProducer.mCondition = ConditionState::kTrue;
 
     vector<shared_ptr<LogEvent>> allData;
     valueProducer.onDataPulled(allData, /** succeed */ false, bucketStartTimeNs);
@@ -2226,7 +2226,7 @@
                                       eventMatcherWizard, tagId, bucketStartTimeNs,
                                       bucketStartTimeNs, pullerManager);
 
-    valueProducer.mCondition = false;
+    valueProducer.mCondition = ConditionState::kFalse;
 
     // Max delay is set to 0 so pull will exceed max delay.
     valueProducer.onConditionChanged(true, bucketStartTimeNs + 1);
@@ -2257,7 +2257,7 @@
                                       eventMatcherWizard, tagId, bucket2StartTimeNs,
                                       bucket2StartTimeNs, pullerManager);
 
-    valueProducer.mCondition = false;
+    valueProducer.mCondition = ConditionState::kFalse;
 
     // Event should be skipped since it is from previous bucket.
     // Pull should not be called.
@@ -2299,7 +2299,7 @@
                                       eventMatcherWizard, tagId, bucketStartTimeNs,
                                       bucketStartTimeNs, pullerManager);
 
-    valueProducer.mCondition = false;
+    valueProducer.mCondition = ConditionState::kFalse;
     valueProducer.mHasGlobalBase = false;
 
     valueProducer.onConditionChanged(true, bucketStartTimeNs + 1);
@@ -2351,7 +2351,7 @@
                                       eventMatcherWizard, tagId, bucketStartTimeNs,
                                       bucketStartTimeNs, pullerManager);
 
-    valueProducer.mCondition = true;
+    valueProducer.mCondition = ConditionState::kTrue;
 
     // Bucket start.
     vector<shared_ptr<LogEvent>> allData;
@@ -2429,7 +2429,7 @@
                                       eventMatcherWizard, tagId, bucketStartTimeNs,
                                       bucketStartTimeNs, pullerManager);
 
-    valueProducer.mCondition = false;
+    valueProducer.mCondition = ConditionState::kFalse;
     valueProducer.onConditionChanged(true, bucket2StartTimeNs + 2);
     EXPECT_EQ(true, valueProducer.mCurrentBucketIsInvalid);
     EXPECT_EQ(0UL, valueProducer.mCurrentSlicedBucket.size());
@@ -2481,7 +2481,7 @@
                                       eventMatcherWizard, tagId, bucketStartTimeNs,
                                       bucketStartTimeNs, pullerManager);
 
-    valueProducer.mCondition = true;
+    valueProducer.mCondition = ConditionState::kTrue;
 
     // Bucket start.
     vector<shared_ptr<LogEvent>> allData;
@@ -2564,7 +2564,7 @@
                                       eventMatcherWizard, tagId, bucketStartTimeNs,
                                       bucketStartTimeNs, pullerManager);
 
-    valueProducer.mCondition = true;
+    valueProducer.mCondition = ConditionState::kTrue;
 
     // Bucket start.
     vector<shared_ptr<LogEvent>> allData;