"This costume is in use" error

System

I've got a large number of reskinned NPCs on the map. When I reloaded the project to work on it, today, attempting to move or change the costume on any given actor gives me a "This costume is in use in X places in the story and on the maps. Continue anyway?" Clicking no cancels my attempt to move or reskin. Clicking yes causes all the actors, regardless of type, to lose their custom costume settings and revert, then not be alterable. I've tried a force verify but it doesn't seem to help.

Project ID: ST-TNGP93JKB, notable on group 'Neutral Talkers.'

Archived Post

I deleted the character I had been using to edit and test the project. The new character got the "costume is in use" error upon opening the project, and all the custom costumes in one room of the map were reset. They seem to be letting me reskin them happily enough now, though when I hit the same threshold we'll have to see if the error recurs.