This exact issue has been discussed earlier and should hopefully become less of an issue going forward as various OAuth using project switch to using editor IDs internally instead of usernames.
That doesn’t help you right now though, and even if that linked discussion doesn’t say anything about what to do if affected, I’m pretty sure the agreement during some other discussion (maybe outside of a meeting) was to write support@metabrainz.org about it and it’d be looked into.