diff --git a/pulsar-broker/src/test/java/org/apache/pulsar/broker/service/persistent/PersistentStreamingDispatcherBlockConsumerTest.java b/pulsar-broker/src/test/java/org/apache/pulsar/broker/service/persistent/PersistentStreamingDispatcherBlockConsumerTest.java
index c0259ae375c47..a3d319ca0c591 100644
--- a/pulsar-broker/src/test/java/org/apache/pulsar/broker/service/persistent/PersistentStreamingDispatcherBlockConsumerTest.java
+++ b/pulsar-broker/src/test/java/org/apache/pulsar/broker/service/persistent/PersistentStreamingDispatcherBlockConsumerTest.java
@@ -26,7 +26,7 @@
 /**
  * DispatcherBlockConsumerTest with {@link StreamingDispatcher}
  */
-@Test(groups = "flaky")
+@Test(groups = "broker")
 public class PersistentStreamingDispatcherBlockConsumerTest extends DispatcherBlockConsumerTest {
 
     @BeforeMethod
diff --git a/pulsar-broker/src/test/java/org/apache/pulsar/client/api/DispatcherBlockConsumerTest.java b/pulsar-broker/src/test/java/org/apache/pulsar/client/api/DispatcherBlockConsumerTest.java
index 1a56d689799be..7696afdeb2885 100644
--- a/pulsar-broker/src/test/java/org/apache/pulsar/client/api/DispatcherBlockConsumerTest.java
+++ b/pulsar-broker/src/test/java/org/apache/pulsar/client/api/DispatcherBlockConsumerTest.java
@@ -56,6 +56,7 @@
 import org.apache.pulsar.common.policies.data.SubscriptionStats;
 import org.apache.pulsar.common.policies.data.TopicStats;
 import org.apache.pulsar.common.util.collections.ConcurrentOpenHashSet;
+import org.awaitility.Awaitility;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.testng.annotations.AfterMethod;
@@ -64,7 +65,7 @@
 import org.testng.annotations.Test;
 import org.testng.collections.Lists;
 
-@Test(groups = "flaky")
+@Test(groups = "broker")
 public class DispatcherBlockConsumerTest extends ProducerConsumerBase {
     private static final Logger log = LoggerFactory.getLogger(DispatcherBlockConsumerTest.class);
 
@@ -998,6 +999,11 @@ public void testBrokerDispatchBlockAndSubAckBackRequiredMsgs() {
              * maxUnAckPerDispatcher limit
              **/
             consumer1Sub2 = (ConsumerImpl<byte[]>) pulsarClient.newConsumer().topic(topicName)
+                    // in the scope of this test is important to not group acks because
+                    // the ack for messages happens after receiving a new message from the topic.
+                    // If the acks are sent in batch it may happen that the dispatcher is still blocked until
+                    // it receives the batched acks and the Consumer#receive will return null.
+                    .acknowledgmentGroupTime(0, TimeUnit.SECONDS)
                     .subscriptionName(subscriberName2).receiverQueueSize(receiverQueueSize)
                     .subscriptionType(SubscriptionType.Shared).subscribe();
             Set<MessageId> messages2 = Sets.newHashSet();
@@ -1014,15 +1020,15 @@ public void testBrokerDispatchBlockAndSubAckBackRequiredMsgs() {
             assertEquals(blockedDispatchers.size(), 2);
 
             // (2.c) Now subscriber-2 is blocked: so acking back should unblock dispatcher
+            // Ack a sublist of unacked messages. The acked messages must unblock the dispatcher and they must be
+            // more than maxUnAckPerDispatcher's half
             Iterator<MessageId> itrMsgs = messages2.iterator();
             int additionalMsgConsumedAfterBlocked = messages2.size() - maxUnAckPerDispatcher + 1; // eg. 25 -20 = 5
             for (int i = 0; i < (additionalMsgConsumedAfterBlocked + (maxUnAckPerDispatcher / 2)); i++) {
                 consumer1Sub2.acknowledge(itrMsgs.next());
             }
-            // let ack completed
-            Thread.sleep(1000);
             // verify subscriber2 is unblocked and ready to consume more messages
-            assertEquals(blockedDispatchers.size(), 1);
+            Awaitility.await().untilAsserted(() -> assertEquals(blockedDispatchers.size(), 1));
             for (int j = 0; j < totalProducedMsgs; j++) {
                 msg = consumer1Sub2.receive(200, TimeUnit.MILLISECONDS);
                 if (msg != null) {