diff --git a/src/main/java/io/reactivex/internal/operators/flowable/FlowableBufferTimed.java b/src/main/java/io/reactivex/internal/operators/flowable/FlowableBufferTimed.java
index f6320ced12..2597a6d140 100644
--- a/src/main/java/io/reactivex/internal/operators/flowable/FlowableBufferTimed.java
+++ b/src/main/java/io/reactivex/internal/operators/flowable/FlowableBufferTimed.java
@@ -166,7 +166,7 @@ public void onComplete() {
             queue.offer(b);
             done = true;
             if (enter()) {
-                QueueDrainHelper.drainMaxLoop(queue, actual, false, this, this);
+                QueueDrainHelper.drainMaxLoop(queue, actual, false, null, this);
             }
         }
 
diff --git a/src/main/java/io/reactivex/internal/operators/observable/ObservableBufferTimed.java b/src/main/java/io/reactivex/internal/operators/observable/ObservableBufferTimed.java
index d521ebae80..2bc4bfbec9 100644
--- a/src/main/java/io/reactivex/internal/operators/observable/ObservableBufferTimed.java
+++ b/src/main/java/io/reactivex/internal/operators/observable/ObservableBufferTimed.java
@@ -161,7 +161,7 @@ public void onComplete() {
                 queue.offer(b);
                 done = true;
                 if (enter()) {
-                    QueueDrainHelper.drainLoop(queue, actual, false, this, this);
+                    QueueDrainHelper.drainLoop(queue, actual, false, null, this);
                 }
             }
             DisposableHelper.dispose(timer);
diff --git a/src/main/java/io/reactivex/internal/util/QueueDrainHelper.java b/src/main/java/io/reactivex/internal/util/QueueDrainHelper.java
index 2964812c4d..25126b3327 100644
--- a/src/main/java/io/reactivex/internal/util/QueueDrainHelper.java
+++ b/src/main/java/io/reactivex/internal/util/QueueDrainHelper.java
@@ -168,7 +168,9 @@ public static <T, U> boolean checkTerminated(boolean d, boolean empty,
         if (d) {
             if (delayError) {
                 if (empty) {
-                    disposable.dispose();
+                    if (disposable != null) {
+                        disposable.dispose();
+                    }
                     Throwable err = qd.error();
                     if (err != null) {
                         s.onError(err);
@@ -181,12 +183,16 @@ public static <T, U> boolean checkTerminated(boolean d, boolean empty,
                 Throwable err = qd.error();
                 if (err != null) {
                     q.clear();
-                    disposable.dispose();
+                    if (disposable != null) {
+                        disposable.dispose();
+                    }
                     s.onError(err);
                     return true;
                 } else
                 if (empty) {
-                    disposable.dispose();
+                    if (disposable != null) {
+                        disposable.dispose();
+                    }
                     s.onComplete();
                     return true;
                 }
diff --git a/src/test/java/io/reactivex/internal/operators/flowable/FlowableBufferTest.java b/src/test/java/io/reactivex/internal/operators/flowable/FlowableBufferTest.java
index d2ebe2ca11..bd18c0187d 100644
--- a/src/test/java/io/reactivex/internal/operators/flowable/FlowableBufferTest.java
+++ b/src/test/java/io/reactivex/internal/operators/flowable/FlowableBufferTest.java
@@ -2014,4 +2014,64 @@ public void run() {
             assertEquals("Round: " + i, 5, items);
         }
     }
+
+    @SuppressWarnings("unchecked")
+    @Test
+    public void noCompletionCancelExact() {
+        final AtomicInteger counter = new AtomicInteger();
+
+        Flowable.<Integer>empty()
+        .doOnCancel(new Action() {
+            @Override
+            public void run() throws Exception {
+                counter.getAndIncrement();
+            }
+        })
+        .buffer(5, TimeUnit.SECONDS)
+        .test()
+        .awaitDone(5, TimeUnit.SECONDS)
+        .assertResult(Collections.<Integer>emptyList());
+
+        assertEquals(0, counter.get());
+    }
+
+    @SuppressWarnings("unchecked")
+    @Test
+    public void noCompletionCancelSkip() {
+        final AtomicInteger counter = new AtomicInteger();
+
+        Flowable.<Integer>empty()
+        .doOnCancel(new Action() {
+            @Override
+            public void run() throws Exception {
+                counter.getAndIncrement();
+            }
+        })
+        .buffer(5, 10, TimeUnit.SECONDS)
+        .test()
+        .awaitDone(5, TimeUnit.SECONDS)
+        .assertResult(Collections.<Integer>emptyList());
+
+        assertEquals(0, counter.get());
+    }
+
+    @SuppressWarnings("unchecked")
+    @Test
+    public void noCompletionCancelOverlap() {
+        final AtomicInteger counter = new AtomicInteger();
+
+        Flowable.<Integer>empty()
+        .doOnCancel(new Action() {
+            @Override
+            public void run() throws Exception {
+                counter.getAndIncrement();
+            }
+        })
+        .buffer(10, 5, TimeUnit.SECONDS)
+        .test()
+        .awaitDone(5, TimeUnit.SECONDS)
+        .assertResult(Collections.<Integer>emptyList());
+
+        assertEquals(0, counter.get());
+    }
 }
diff --git a/src/test/java/io/reactivex/internal/operators/observable/ObservableBufferTest.java b/src/test/java/io/reactivex/internal/operators/observable/ObservableBufferTest.java
index d7b6046e42..93a9e2fb74 100644
--- a/src/test/java/io/reactivex/internal/operators/observable/ObservableBufferTest.java
+++ b/src/test/java/io/reactivex/internal/operators/observable/ObservableBufferTest.java
@@ -19,6 +19,7 @@
 
 import java.util.*;
 import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import org.junit.*;
 import org.mockito.*;
@@ -1439,4 +1440,64 @@ public void run() {
             assertEquals("Round: " + i, 5, items);
         }
     }
+
+    @SuppressWarnings("unchecked")
+    @Test
+    public void noCompletionCancelExact() {
+        final AtomicInteger counter = new AtomicInteger();
+
+        Observable.<Integer>empty()
+        .doOnDispose(new Action() {
+            @Override
+            public void run() throws Exception {
+                counter.getAndIncrement();
+            }
+        })
+        .buffer(5, TimeUnit.SECONDS)
+        .test()
+        .awaitDone(5, TimeUnit.SECONDS)
+        .assertResult(Collections.<Integer>emptyList());
+
+        assertEquals(0, counter.get());
+    }
+
+    @SuppressWarnings("unchecked")
+    @Test
+    public void noCompletionCancelSkip() {
+        final AtomicInteger counter = new AtomicInteger();
+
+        Observable.<Integer>empty()
+        .doOnDispose(new Action() {
+            @Override
+            public void run() throws Exception {
+                counter.getAndIncrement();
+            }
+        })
+        .buffer(5, 10, TimeUnit.SECONDS)
+        .test()
+        .awaitDone(5, TimeUnit.SECONDS)
+        .assertResult(Collections.<Integer>emptyList());
+
+        assertEquals(0, counter.get());
+    }
+
+    @SuppressWarnings("unchecked")
+    @Test
+    public void noCompletionCancelOverlap() {
+        final AtomicInteger counter = new AtomicInteger();
+
+        Observable.<Integer>empty()
+        .doOnDispose(new Action() {
+            @Override
+            public void run() throws Exception {
+                counter.getAndIncrement();
+            }
+        })
+        .buffer(10, 5, TimeUnit.SECONDS)
+        .test()
+        .awaitDone(5, TimeUnit.SECONDS)
+        .assertResult(Collections.<Integer>emptyList());
+
+        assertEquals(0, counter.get());
+    }
 }