diff --git a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/spi/v1/PollingSubscriberConnection.java b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/spi/v1/PollingSubscriberConnection.java
index da9b64282ac9..f727972a2b7a 100644
--- a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/spi/v1/PollingSubscriberConnection.java
+++ b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/spi/v1/PollingSubscriberConnection.java
@@ -127,6 +127,9 @@ protected void doStop() {
   }
 
   private void pullMessages(final Duration backoff) {
+    if (!isAlive()) {
+      return;
+    }
     ListenableFuture<PullResponse> pullResult =
         stub.withDeadlineAfter(DEFAULT_TIMEOUT.toMillis(), TimeUnit.MILLISECONDS)
             .pull(
@@ -201,7 +204,9 @@ public void run() {
   }
 
   private boolean isAlive() {
-    return state() == State.RUNNING || state() == State.STARTING;
+    // Read state only once. Because of threading, different calls can give different results.
+    State state = state();
+    return state == State.RUNNING || state == State.STARTING;
   }
 
   @Override