diff --git a/smallrye-reactive-messaging-pulsar/src/main/java/io/smallrye/reactive/messaging/pulsar/PulsarIncomingBatchMessage.java b/smallrye-reactive-messaging-pulsar/src/main/java/io/smallrye/reactive/messaging/pulsar/PulsarIncomingBatchMessage.java
index daae983c3f..9f01746408 100644
--- a/smallrye-reactive-messaging-pulsar/src/main/java/io/smallrye/reactive/messaging/pulsar/PulsarIncomingBatchMessage.java
+++ b/smallrye-reactive-messaging-pulsar/src/main/java/io/smallrye/reactive/messaging/pulsar/PulsarIncomingBatchMessage.java
@@ -73,7 +73,7 @@ public CompletionStage<Void> ack() {
                         return stream;
                     }
                 })
-                .onItem().transformToUniAndConcatenate(m -> Uni.createFrom().completionStage(m.getAck()))
+                .onItem().transformToUniAndMerge(m -> Uni.createFrom().completionStage(m.getAck()))
                 .toUni().subscribeAsCompletionStage();
     }
 
@@ -85,7 +85,7 @@ public Supplier<CompletionStage<Void>> getAck() {
     @Override
     public CompletionStage<Void> nack(Throwable reason, Metadata metadata) {
         return Multi.createFrom().iterable(incomingMessages)
-                .onItem().transformToUniAndConcatenate(m -> Uni.createFrom().completionStage(m.nack(reason, metadata)))
+                .onItem().transformToUniAndMerge(m -> Uni.createFrom().completionStage(m.nack(reason, metadata)))
                 .toUni().subscribeAsCompletionStage();
     }
 
diff --git a/smallrye-reactive-messaging-pulsar/src/test/java/io/smallrye/reactive/messaging/pulsar/base/PulsarContainer.java b/smallrye-reactive-messaging-pulsar/src/test/java/io/smallrye/reactive/messaging/pulsar/base/PulsarContainer.java
index 108e7dfbb9..e31837e619 100644
--- a/smallrye-reactive-messaging-pulsar/src/test/java/io/smallrye/reactive/messaging/pulsar/base/PulsarContainer.java
+++ b/smallrye-reactive-messaging-pulsar/src/test/java/io/smallrye/reactive/messaging/pulsar/base/PulsarContainer.java
@@ -47,6 +47,10 @@ protected void containerIsStarting(InspectContainerResponse containerInfo, boole
         command += "export PULSAR_PREFIX_advertisedListeners=" + advertisedListeners + " \n";
         command += "export PULSAR_PREFIX_transactionCoordinatorEnabled=true\n";
         command += "export PULSAR_PREFIX_systemTopicEnabled=true\n";
+        command += "export PULSAR_PREFIX_brokerDeduplicationEnabled=true\n";
+        command += "export PULSAR_PREFIX_brokerDeduplicationEntriesInterval=100\n";
+        command += "export PULSAR_PREFIX_brokerDeduplicationSnapshotIntervalSeconds=3000\n";
+        command += "export PULSAR_PREFIX_acknowledgmentAtBatchIndexLevelEnabled=true\n";
         command += "bin/apply-config-from-env.py conf/standalone.conf && bin/pulsar standalone -nfw -nss";
         copyFileToContainer(
                 Transferable.of(command.getBytes(StandardCharsets.UTF_8), 700),
diff --git a/smallrye-reactive-messaging-pulsar/src/test/java/io/smallrye/reactive/messaging/pulsar/fault/PulsarNackTest.java b/smallrye-reactive-messaging-pulsar/src/test/java/io/smallrye/reactive/messaging/pulsar/fault/PulsarNackTest.java
index 9781573f52..c7a4dfb37a 100644
--- a/smallrye-reactive-messaging-pulsar/src/test/java/io/smallrye/reactive/messaging/pulsar/fault/PulsarNackTest.java
+++ b/smallrye-reactive-messaging-pulsar/src/test/java/io/smallrye/reactive/messaging/pulsar/fault/PulsarNackTest.java
@@ -117,7 +117,6 @@ void testReconsumeLater() throws PulsarClientException {
 
     @Test
     void testDeadLetterTopic() throws PulsarClientException {
-        addBeans(PulsarReconsumeLater.Factory.class);
         // Run app
         FailingConsumingApp app = runApplication(config()
                 .with("mp.messaging.incoming.data.failure-strategy", "nack")
@@ -126,13 +125,14 @@ void testDeadLetterTopic() throws PulsarClientException {
                 .with("mp.messaging.incoming.data.deadLetterPolicy.maxRedeliverCount", 2)
                 .with("mp.messaging.incoming.data.deadLetterPolicy.deadLetterTopic", topic + "-dlq")
                 .with("mp.messaging.incoming.data.deadLetterPolicy.initialSubscriptionName", "initial-dlq-sub")
+                .with("mp.messaging.incoming.data.deadLetterPolicy.batchIndexAckEnabled", true)
                 .with("mp.messaging.incoming.data.subscriptionType", "Shared"), FailingConsumingApp.class);
         // Produce messages
         send(client.newProducer(Schema.INT32)
                 .producerName("test-producer")
                 .enableBatching(false)
                 .topic(topic)
-                .create(), NUMBER_OF_MESSAGES, i -> i);
+                .create(), NUMBER_OF_MESSAGES, (i, p) -> p.newMessage().sequenceId(i).value(i));
 
         // Check for consumed messages in app
         await().untilAsserted(() -> {
@@ -142,9 +142,11 @@ void testDeadLetterTopic() throws PulsarClientException {
 
         List<Message<Integer>> retries = new CopyOnWriteArrayList<>();
         receive(client.newConsumer(Schema.INT32)
+                .consumerName("dlq-consumer")
                 .topic(topic + "-dlq")
                 .subscriptionInitialPosition(SubscriptionInitialPosition.Earliest)
                 .subscriptionName("initial-dlq-sub")
+                .enableBatchIndexAcknowledgment(true)
                 .subscribe()).subscribe().with(retries::add);
 
         // Check for retried messages
diff --git a/smallrye-reactive-messaging-pulsar/src/test/java/io/smallrye/reactive/messaging/pulsar/transactions/ExactlyOnceProcessingBatchTest.java b/smallrye-reactive-messaging-pulsar/src/test/java/io/smallrye/reactive/messaging/pulsar/transactions/ExactlyOnceProcessingBatchTest.java
index 0b4fc529ee..009a303ef0 100644
--- a/smallrye-reactive-messaging-pulsar/src/test/java/io/smallrye/reactive/messaging/pulsar/transactions/ExactlyOnceProcessingBatchTest.java
+++ b/smallrye-reactive-messaging-pulsar/src/test/java/io/smallrye/reactive/messaging/pulsar/transactions/ExactlyOnceProcessingBatchTest.java
@@ -25,9 +25,6 @@
 import org.eclipse.microprofile.reactive.messaging.Channel;
 import org.eclipse.microprofile.reactive.messaging.Incoming;
 import org.eclipse.microprofile.reactive.messaging.OnOverflow;
-import org.junit.jupiter.api.Disabled;
-import org.junit.jupiter.api.RepeatedTest;
-import org.junit.jupiter.api.Tag;
 import org.junit.jupiter.api.Test;
 
 import io.smallrye.common.annotation.Identifier;
@@ -35,7 +32,6 @@
 import io.smallrye.reactive.messaging.pulsar.PulsarConnector;
 import io.smallrye.reactive.messaging.pulsar.PulsarIncomingBatchMessage;
 import io.smallrye.reactive.messaging.pulsar.PulsarMessage;
-import io.smallrye.reactive.messaging.pulsar.TestTags;
 import io.smallrye.reactive.messaging.pulsar.base.WeldTestBase;
 import io.smallrye.reactive.messaging.test.common.config.MapBasedConfig;
 
@@ -92,17 +88,13 @@ Uni<Void> process(PulsarIncomingBatchMessage<Integer> batch) {
     }
 
     /**
-     * TODO Disabled test
      * For exactly-once processing the broker needs to enable the Message deduplication with
      * broker config <code>brokerDeduplicationEnabled=true</code> and producer `sendTimeoutMs` needs to be `0`.
      *
-     * However only this doesn't solve the issue of duplicated items.
-     *
      * There is also batch index level acknowledgement to avoid duplicated items which can be enabled with,
      * The broker config <code>acknowledgmentAtBatchIndexLevelEnabled=true</code> and consumer config `batchIndexAckEnable` to
      * `true.
      *
-     * There are still duplicate items delivered to the consumer batch after an transaction abort.
      */
     @Test
     void testExactlyOnceProcessorWithProcessingError() throws PulsarAdminException, PulsarClientException {
@@ -125,8 +117,6 @@ void testExactlyOnceProcessorWithProcessingError() throws PulsarAdminException,
                 .enableBatchIndexAcknowledgment(true)
                 .subscribe()).subscribe().with(messages -> {
                     for (Message<Integer> message : messages) {
-                        System.out.println(
-                                "-received " + message.getSequenceId() + " - " + message.getKey() + ":" + message.getValue());
                         list.add(message.getValue());
                     }
                 });