Thanks James.
Actually, I lucked into a solution without that “deactivate all plugins” approach.
The other 2 users do not regularly clear their browser caches. I do every single day. So, by getting them to clear cache and retry it seemed to have resolved the issue.
It must have been a conflict between the 5.1 cached Editor and the 5.2 Editor that caused the issue.
Problem solved. Thanks again
