Failure "Error - _55.getEnumerationValue is not a function, when creating child workitems

RTC 6.0.2, iFix005 with following observation:
when adding a child work item (task) to a user story that was created by someone else, I get a failure "Error - _55.getEnumerationValue is not a function.
The task will be created, either for "unassigned" or for the owner of the parent task, but not for me directly.  I can assign the task to me and so on. But it is very cumbersome to handle it this way.

This failure does not show up when adding child tasks to my own user stories.