diff --git a/x-pack/qa/rolling-upgrade/src/test/java/org/elasticsearch/upgrades/MlMigrationIT.java b/x-pack/qa/rolling-upgrade/src/test/java/org/elasticsearch/upgrades/MlMigrationIT.java
index 8ffbb7184b4b3..6d4014a1d7e4c 100644
--- a/x-pack/qa/rolling-upgrade/src/test/java/org/elasticsearch/upgrades/MlMigrationIT.java
+++ b/x-pack/qa/rolling-upgrade/src/test/java/org/elasticsearch/upgrades/MlMigrationIT.java
@@ -204,12 +204,15 @@ private void upgradedClusterTests() throws Exception {
             datafeedStarted = startMigratedDatafeed(OLD_CLUSTER_STOPPED_DATAFEED_ID);
         }
 
-        // wait for the closed and open jobs and datafeed to be migrated
-        waitForMigration(Arrays.asList(OLD_CLUSTER_CLOSED_JOB_ID, OLD_CLUSTER_OPEN_JOB_ID),
-                Arrays.asList(OLD_CLUSTER_STOPPED_DATAFEED_ID, OLD_CLUSTER_STARTED_DATAFEED_ID));
+        // wait for the closed job and datafeed to be migrated
+        waitForMigration(OLD_CLUSTER_CLOSED_JOB_ID, OLD_CLUSTER_STOPPED_DATAFEED_ID);
 
-        checkTaskParamsAreUpdated(OLD_CLUSTER_OPEN_JOB_ID, OLD_CLUSTER_STARTED_DATAFEED_ID);
-        checkJobsMarkedAsMigrated(Arrays.asList(OLD_CLUSTER_CLOSED_JOB_ID, OLD_CLUSTER_OPEN_JOB_ID));
+        // The open job and datafeed may or may not be migrated depending on how they were allocated.
+        // Migration will only occur once all nodes in the cluster are v6.6.0 or higher
+        // open jobs will only be migrated once they become unallocated. The open job
+        // will only meet these conditions if it is running on the last node to be
+        // upgraded
+        waitForPossibleMigration(OLD_CLUSTER_OPEN_JOB_ID, OLD_CLUSTER_STARTED_DATAFEED_ID);
 
         // the job and datafeed left open during upgrade should
         // be assigned to a node
@@ -234,6 +237,11 @@ private void upgradedClusterTests() throws Exception {
         Request closeJob = new Request("POST", "_xpack/ml/anomaly_detectors/" + OLD_CLUSTER_OPEN_JOB_ID + "/_close");
         client().performRequest(closeJob);
 
+        // if the open job wasn't migrated previously it should be now after it has been closed
+        waitForMigration(OLD_CLUSTER_OPEN_JOB_ID, OLD_CLUSTER_STARTED_DATAFEED_ID);
+        checkJobsMarkedAsMigrated(Arrays.asList(OLD_CLUSTER_CLOSED_JOB_ID, OLD_CLUSTER_OPEN_JOB_ID));
+
+        // and the job left open can be deleted
         Request deleteDatafeed = new Request("DELETE", "_xpack/ml/datafeeds/" + OLD_CLUSTER_STARTED_DATAFEED_ID);
         client().performRequest(deleteDatafeed);
         Request deleteJob = new Request("DELETE", "_xpack/ml/anomaly_detectors/" + OLD_CLUSTER_OPEN_JOB_ID);
@@ -323,7 +331,7 @@ private void checkJobsMarkedAsMigrated(List<String> jobIds) throws IOException {
     }
 
     @SuppressWarnings("unchecked")
-    private void checkTaskParamsAreUpdated(String jobId, String datafeedId) throws Exception {
+    private void checkTaskParams(String jobId, String datafeedId, boolean expectedUpdated) throws Exception {
         Request getClusterState = new Request("GET", "/_cluster/state/metadata");
         Response response = client().performRequest(getClusterState);
         Map<String, Object> responseMap = entityAsMap(response);
@@ -336,12 +344,21 @@ private void checkTaskParamsAreUpdated(String jobId, String datafeedId) throws E
             assertNotNull(id);
             if (id.equals(MlTasks.jobTaskId(jobId))) {
                 Object jobParam = XContentMapValues.extractValue("task.xpack/ml/job.params.job", task);
-                assertNotNull(jobParam);
+                if (expectedUpdated) {
+                    assertNotNull(jobParam);
+                } else {
+                    assertNull(jobParam);
+                }
             } else if (id.equals(MlTasks.datafeedTaskId(datafeedId))) {
                 Object jobIdParam = XContentMapValues.extractValue("task.xpack/ml/datafeed.params.job_id", task);
-                assertNotNull(jobIdParam);
                 Object indices = XContentMapValues.extractValue("task.xpack/ml/datafeed.params.indices", task);
-                assertNotNull(indices);
+                if (expectedUpdated) {
+                    assertNotNull(jobIdParam);
+                    assertNotNull(indices);
+                } else {
+                    assertNull(jobIdParam);
+                    assertNull(indices);
+                }
             }
         }
     }
@@ -373,7 +390,7 @@ private void assertConfigInClusterState() throws IOException {
     }
 
     @SuppressWarnings("unchecked")
-    private void waitForMigration(List<String> expectedMigratedJobs, List<String> expectedMigratedDatafeeds) throws Exception {
+    private void waitForMigration(String expectedMigratedJobId, String expectedMigratedDatafeedId) throws Exception {
         assertBusy(() -> {
             // wait for the eligible configs to be moved from the clusterstate
             Request getClusterState = new Request("GET", "/_cluster/state/metadata");
@@ -384,23 +401,55 @@ private void waitForMigration(List<String> expectedMigratedJobs, List<String> ex
                     (List<Map<String, Object>>) XContentMapValues.extractValue("metadata.ml.jobs", responseMap);
 
             if (jobs != null) {
-                for (String jobId : expectedMigratedJobs) {
-                    assertJobMigrated(jobId, jobs);
-                }
+                assertJobMigrated(expectedMigratedJobId, jobs);
             }
 
             List<Map<String, Object>> datafeeds =
                     (List<Map<String, Object>>) XContentMapValues.extractValue("metadata.ml.datafeeds", responseMap);
 
             if (datafeeds != null) {
-                for (String datafeedId : expectedMigratedDatafeeds) {
-                    assertDatafeedMigrated(datafeedId, datafeeds);
-                }
+                assertDatafeedMigrated(expectedMigratedDatafeedId, datafeeds);
             }
 
         }, 30, TimeUnit.SECONDS);
     }
 
+    @SuppressWarnings("unchecked")
+    private void waitForPossibleMigration(String perhapsMigratedJobId, String perhapsMigratedDatafeedId) throws Exception {
+        assertBusy(() -> {
+            Request getClusterState = new Request("GET", "/_cluster/state/metadata");
+            Response response = client().performRequest(getClusterState);
+            Map<String, Object> responseMap = entityAsMap(response);
+
+            List<Map<String, Object>> jobs =
+                    (List<Map<String, Object>>) XContentMapValues.extractValue("metadata.ml.jobs", responseMap);
+
+            boolean jobMigrated = true;
+            if (jobs != null) {
+                jobMigrated = jobs.stream().map(map -> map.get("job_id"))
+                        .noneMatch(id -> id.equals(perhapsMigratedJobId));
+            }
+
+            List<Map<String, Object>> datafeeds =
+                    (List<Map<String, Object>>) XContentMapValues.extractValue("metadata.ml.datafeeds", responseMap);
+
+            boolean datafeedMigrated = true;
+            if (datafeeds != null) {
+                datafeedMigrated = datafeeds.stream().map(map -> map.get("datafeed_id"))
+                        .noneMatch(id -> id.equals(perhapsMigratedDatafeedId));
+            }
+
+            if (jobMigrated) {
+                // if the job is migrated the datafeed should also be
+                assertTrue(datafeedMigrated);
+                checkJobsMarkedAsMigrated(Collections.singletonList(perhapsMigratedJobId));
+            }
+
+            // if migrated the persistent task params should have been updated
+            checkTaskParams(perhapsMigratedJobId, perhapsMigratedDatafeedId, jobMigrated);
+        });
+    }
+
     @SuppressWarnings("unchecked")
     private void waitForJobToBeAssigned(String jobId) throws Exception {
         assertBusy(() -> {