🇬🇧United Kingdom @jonhalle

Thank you @markusa. Yes that does allow it to work - though clearly it's a diagnostic step not a workaround. Does that give any more clues? Happy to do some more poking but I am not really clear on what structures in Drupal this hook is seeking to update.

One additional thing I have noticed is that the error does not stop the case being created, albeit with only the activities up to the one with the pre-assigned user being created.

jonhalle → created an issue.