While investigating Sentry errors, I ran into this user who was retired in Oct.2022, but the created a new account with the same email in Sept 2023.
Now it looks like the new account they created on MITxOnline is now associated with the old edx account. I guess it got reactevated.
There is one active enrollment:
https://courses.mitxonline.mit.edu/admin/student/courseenrollment/?q=mdelrioar