When working on https://bugzilla.redhat.com/show_bug.cgi?id=1876635 I tried to clean up one of the NEEDINFO set by me, and I'm not allowed to do that. When I empty the field by setting "" instead of "?" and press save, I get a "You must select/enter a user." error. I saw this after a complain of another user (the one that has the NEEDINFO set to) that she was unable to clear it and also that she was unable to set NEEDINFO for me.
*** This bug has been marked as a duplicate of bug 1886889 ***