We have several flows in Architect but until recently have noticed that the category for the call bridge actions disassociating itself with the flow.

Doesn't matter how many times we save a copy and attempt to republish the flow it continues to follow. This prevents us from publishing updates, Has anyone experienced the same?

Have raised a support ticket and awaiting a bug fix.

I think I found your support ticket.   We deployed a fix for the issue with the category being lost several weeks ago.  If this is still happening, please let support know.  Also can you give me the exact steps you're using?  I'm having trouble reproducing this, even using an old build of architect without the fix.