Okay. Here's two versions of it with some further checks added. If helpful people who're experiencing the lockup could try them out and let me know what happens I would be most appreciative.
First: FuBar_QuestsFu-0.2.1.1.a.zip is just 0.2.1 with some extra error-checking to try to prevent infinite loops.
Second: FuBar_QuestsFu-0.2.1.1.b.zip is 0.2.1.1.a with the objective-displaying in the tooltip ripped out.
I have some people
mentioning that setting up character-specific profiles stopped it for them. I'm not sure why this would be, as I'm not storing anything particularly important. Especially not anything involved in loops.