Hi Anders, I have also been seeing some issues when adding/modidying heading tags (C-c C-q), and I was able to narrow it down to the element caching mechanism.
Issue: Org mode/Emacs hangs kind of indefinitely when I do C-c C-q, but that doesn't happen each time. Once I set org-element-use-cache to nil, Emacs stopped hanging. Looking at your bug report, I believe that the issue I am seeing with cache and Org tags could be very much related. So thanks for submitting this. -- Kaushal Modi
