Auto-number Update: We've just run this to rename the prefix. We tick UPDATE and SAVE. Some records are updated, other not. Been over 18 hours now. Anyone else had this?

Are the ones not updating in closed periods? I've never tried doing that update, but depending on your settings, you may not be able to update records in closed periods, even if the change doesn't affect the books.

@RJMNS is 100% correct

(allow non-gl changes -- checkbox on the periods)