Question mark in user name leads to strange behaviour

[nebunez]

I'm running into a problem with a new user on my Snikket instance. I think it was caused when I removed them from the ciricle they were invited too; but I can't delete, view debug information for, or create password reset link for them. I tried adding them back into a circle and that caused the circle's member count to increase by one, but the user is not showing as a member in the admin area (I can still try to "add them" to the circle, even) and I have no evidence that they received an invite. I can share screenshots of the error messages when I try to perform user operations, if that would be helpful.

The username has a '?' character in it, that may be the cause of these issues.

UPDATE: I just noticed that the user showed up in my contacts without the '?' in their name. This appears to be after I tried to add them to the circle earlier. I don't see this username without the '?' anywhere in the admin area.