**Found in version**
- Observed in 8.2.3, but might exist longer

**Steps to reproduce**
On a multi node cloud cluster (might also work on a local multi node cluster):
- Create a transform with a retention policy
- Update the transform and remove the retention policy

**Expected result**
- The retention policy is removed

**Actual result**
- This sometimes results in an error:
```
An error occurred calling the API endpoint to update transforms.
Bad Request: [illegal_argument_exception: [illegal_argument_exception] Reason: 
Unknown NamedWriteable [org.elasticsearch.xpack.core.transform.transforms.RetentionPolicyConfig][null_retention_policy]]:
Unknown NamedWriteable [org.elasticsearch.xpack.core.transform.transforms.RetentionPolicyConfig][null_retention_policy]
```

**Additional information**
- Quote from slack discussion with @benwtrent:
  > It wouldn’t happen if you hit a node that can execute the update immediately without serializing to a different node
x-pack/plugin/transform/qa/multi-node-tests/src/javaRestTest/java/org/elasticsearch/xpack/transform/integration/TransformIT.java
Request settingsRequest = new Request("PUT", "/_cluster/settings");
        settingsRequest.setJsonEntity("""
            {
              "persistent": {
                "logger.org.elasticsearch.xpack.core.indexing.AsyncTwoPhaseIndexer": "debug",
                "logger.org.elasticsearch.xpack.transform": "debug"
              }
            }""");
        client().performRequest(settingsRequest);
    }
    @After
    public void cleanTransforms() throws Exception {
        cleanUp();
    }
    public void testTransformCrud() throws Exception {
        String indexName = "basic-crud-reviews";
        String transformId = "transform-crud";
        createReviewsIndex(indexName, 100, NUM_USERS, TransformIT::getUserIdForRow, TransformIT::getDateStringForRow);
        Map<String, SingleGroupSource> groups = new HashMap<>();
        groups.put("by-day", createDateHistogramGroupSourceWithCalendarInterval("timestamp", DateHistogramInterval.DAY, null));
        groups.put("by-user", new TermsGroupSource("user_id", null, false));
        groups.put("by-business", new TermsGroupSource("business_id", null, false));
        AggregatorFactories.Builder aggs = AggregatorFactories.builder()
            .addAggregator(AggregationBuilders.avg("review_score").field("stars"))
            .addAggregator(AggregationBuilders.max("timestamp").field("timestamp"));
        TransformConfig config = createTransformConfigBuilder(
            transformId,
            "reviews-by-user-business-day",
            QueryConfig.matchAll(),
            indexName