diff --git a/modules/reindex/src/internalClusterTest/java/org/elasticsearch/index/reindex/BulkByScrollUsesAllScrollDocumentsAfterConflictsIntegTests.java b/modules/reindex/src/internalClusterTest/java/org/elasticsearch/index/reindex/BulkByScrollUsesAllScrollDocumentsAfterConflictsIntegTests.java
index a1aceb68967b3..a06f9a0ac2b45 100644
--- a/modules/reindex/src/internalClusterTest/java/org/elasticsearch/index/reindex/BulkByScrollUsesAllScrollDocumentsAfterConflictsIntegTests.java
+++ b/modules/reindex/src/internalClusterTest/java/org/elasticsearch/index/reindex/BulkByScrollUsesAllScrollDocumentsAfterConflictsIntegTests.java
@@ -96,9 +96,9 @@ public void setUpCluster() {
         internalCluster().startMasterOnlyNode();
         // Use a single thread pool for writes so we can enforce a consistent ordering
         internalCluster().startDataOnlyNode(Settings.builder().put("thread_pool.write.size", 1).build());
+        internalCluster().startCoordinatingOnlyNode(Settings.EMPTY);
     }
 
-    @AwaitsFix(bugUrl = "https://github.com/elastic/elasticsearch/issues/79300")
     public void testUpdateByQuery() throws Exception {
         final String indexName = randomAlphaOfLength(10).toLowerCase(Locale.ROOT);
         final boolean scriptEnabled = randomBoolean();
@@ -112,7 +112,6 @@ public void testUpdateByQuery() throws Exception {
         });
     }
 
-    @AwaitsFix(bugUrl = "https://github.com/elastic/elasticsearch/issues/79300")
     public void testReindex() throws Exception {
         final String sourceIndex = randomAlphaOfLength(10).toLowerCase(Locale.ROOT);
         final String targetIndex = randomAlphaOfLength(10).toLowerCase(Locale.ROOT);
@@ -135,7 +134,6 @@ public void testReindex() throws Exception {
         });
     }
 
-    @AwaitsFix(bugUrl = "https://github.com/elastic/elasticsearch/issues/79300")
     public void testDeleteByQuery() throws Exception {
         final String indexName = randomAlphaOfLength(10).toLowerCase(Locale.ROOT);
         executeConcurrentUpdatesOnSubsetOfDocs(indexName,
@@ -217,7 +215,12 @@ Self extends AbstractBulkByScrollRequestBuilder<R, Self>> void executeConcurrent
         }
 
         // The bulk request is enqueued before the update by query
-        final ActionFuture<BulkResponse> bulkFuture = client().bulk(conflictingUpdatesBulkRequest);
+        // Since #77731 TransportBulkAction is dispatched into the Write thread pool,
+        // this test makes use of a deterministic task order in the data node write
+        // thread pool. To ensure that ordering, execute the TransportBulkAction
+        // in a coordinator node preventing that additional tasks are scheduled into
+        // the data node write thread pool.
+        final ActionFuture<BulkResponse> bulkFuture = internalCluster().coordOnlyNodeClient().bulk(conflictingUpdatesBulkRequest);
 
         // Ensure that the concurrent writes are enqueued before the update by query request is sent
         assertBusy(() -> assertThat(writeThreadPool.getQueue().size(), equalTo(1)));