This has happened twice now, so I figured I might as well let you know.
I don't actually have any employees, but I created an employee account for my tech-savvy brother because he was curious about my shop. He doesn't actually use the account much. But the last two times I updated my shop software, the second time being last night, PrestaShop copies his e-mail address to my account. This causes me to be unable to log in on my own account, I have to use his to change my email address back again. Has anybody had this happen as well? I think it's a very weird bug . I'm glad I found out what was wrong before I got stressed out about not being able to log in anymore.