If you use Trello for personal and/or business you may want to review this thread. Similar thing happened to me. The solution, for me, was to remove my work email from my account and keep it personal.
Micro.blog
@AlanRalph This isn't limited to SSO. For me, I had recovery email set as work email, which gave my previous employer the ability to change my password. Not good. So I'd be very wary of setting a recovery email to anything but an email address that you'll always have access to.