**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/core/src/main/java/org/elasticsearch/xpack/core/XPackClientPlugin.java
new NamedWriteableRegistry.Entry(NamedDiff.class, WatcherMetadata.TYPE, WatcherMetadata::readDiffFrom),
                new NamedWriteableRegistry.Entry(XPackFeatureSet.Usage.class, XPackField.WATCHER, WatcherFeatureSetUsage::new),
                
                new NamedWriteableRegistry.Entry(Metadata.Custom.class, LicensesMetadata.TYPE, LicensesMetadata::new),
                new NamedWriteableRegistry.Entry(NamedDiff.class, LicensesMetadata.TYPE, LicensesMetadata::readDiffFrom),
                
                new NamedWriteableRegistry.Entry(XPackFeatureSet.Usage.class, XPackField.ROLLUP, RollupFeatureSetUsage::new),
                new NamedWriteableRegistry.Entry(PersistentTaskParams.class, RollupJob.NAME, RollupJob::new),
                new NamedWriteableRegistry.Entry(Task.Status.class, RollupJobStatus.NAME, RollupJobStatus::new),
                new NamedWriteableRegistry.Entry(PersistentTaskState.class, RollupJobStatus.NAME, RollupJobStatus::new),
                
                new NamedWriteableRegistry.Entry(AutoFollowMetadata.class, AutoFollowMetadata.TYPE, AutoFollowMetadata::new),
                new NamedWriteableRegistry.Entry(Metadata.Custom.class, AutoFollowMetadata.TYPE, AutoFollowMetadata::new),
                new NamedWriteableRegistry.Entry(
                    NamedDiff.class,
                    AutoFollowMetadata.TYPE,
                    in -> AutoFollowMetadata.readDiffFrom(Metadata.Custom.class, AutoFollowMetadata.TYPE, in)
                ),
                
                new NamedWriteableRegistry.Entry(
                    XPackFeatureSet.Usage.class,
                    XPackField.INDEX_LIFECYCLE,
                    IndexLifecycleFeatureSetUsage::new
                ),
                
                new NamedWriteableRegistry.Entry(XPackFeatureSet.Usage.class, XPackField.SNAPSHOT_LIFECYCLE, SLMFeatureSetUsage::new),
                
                new NamedWriteableRegistry.Entry(Metadata.Custom.class, IndexLifecycleMetadata.TYPE, IndexLifecycleMetadata::new),
                new NamedWriteableRegistry.Entry(
                    NamedDiff.class,