most games i've seen that allows CRAUs have a rule along these lines, or require permission before jumping the gun. if someone is pulling that shit without your comfort and consent, you should make sure they're not breaking any rules.

most players i've interacted with seem fine with CRAUs, so you really need to put on your big kid pants and communicate when you're not okay with it. tbh this situation isn't any different than someone new apping up a dropped character who had a ton of CR with other characters still in game. characters are going to remember a different version than the one you're playing and you still need to speak up if they're pushing your boundaries.