Just did another test tonight, removing the Album Artist tag on 4,665 AAC files...
via Extended Tags: ~3 minutes
via Quick Actions: ~3 seconds
IMO, I would definitely say that doing it via Extended Tags is the "buggy" option. Whatever extra code is there to make the process "smoother" I would say is not needed. I mean really, what is the point of having it be "smoother" if it takes almost 3-minutes to complete via Extended Tags? Who on earth would want to wait 3-minutes to modify tags on 4,665 files when it can be done in 3-seconds? Seems like you could easily get rid of that code to minimize footprint and make it faster at the same time. Sounds like a win/win to me lol.