setSyncing(TRUE) prevents saving field value if identical to default revision

Hello,
As documented here: https://www.drupal.org/node/3052114
I use $node->setSyncing(TRUE) to be able to update fields values of the latest revision without creating a new revision.
I have noticed that unfortunately, if the value I try to save is the exact same value that the one stored in the default revision, setSyncing(TRUE) will prevent this value from being saved !

Let me explain a little bit more:
I have a node that has already been published at least once. So its default revision is the last published one. It's the one you would get by doing a simple Node::load($nid)...
Since the last published revision, I have created multiple draft versions. So I have more recent revisions, and I make sure to load the latest one when I try to programmatically updated it:

$revision_ids = \Drupal::entityTypeManager()->getStorage('node')->revisionIds($node);
$last_revision_id = end($revision_ids);
$last_revision = \Drupal::entityTypeManager()->getStorage('node')->loadRevision($last_revision_id);

and then to update one field value of this latest revision, without creating a new revision, I do this:

$last_revision->field_MY_FIELD = "Some value";
$last_revision->setSyncing(TRUE);
$last_revision->save();

This works, but if "Some value" is already the value stored inside the default revision (last published), the value will not be saved (for the last revision which is the one I try to update).

So you can try to change the value to something different than the default version, witness that it's indeed working, saving and not creating a new revision. Then try to put the exact value stored in last published version, and witness that the value is not updated in the last revision.
However, if you comment setSyncing(TRUE) you are able to save the value even if identical to the one of the default revision.