Just a follow-up on this.
We ran a job to attempt to locate and invalidate the “bad” user tokens. This should cause users to need to re-authenticate the app, and get them a valid token.
The other changes were previously rolled back.
We’re hoping that this is now resolved, but if not, if it is possible in your apps to reject the invalid token or force a fresh login, that should help. We’re very sorry for the issues this has caused.