Okay this one was weird, but I figured it out it’s when there’s an unreadable recovered file (the very last item in the project binder). In this case, it was a .styles file leftover/recovered from probably an unexpected shutdown. I don’t remember where it came from.
It may not just be Find Style, it may be any Find routine that inspects an unreadable file–I already deleted the recovered files so I have no way to recreate this anymore, but it was happening without fail until I figured out what it was.
Thanks! Ping if you need more information.