Contributor dropdown has two "undefined" entries. Investigate source of those entries and delete them; there should be no "undefined" entries on that list.
Haven't been able to replicate this bug, unless it's perhaps a user with no name? Anyway, put a few things in here to gut check.
In which case the "undefined" is correct.
Contributor dropdown has two "undefined" entries. Investigate source of those entries and delete them; there should be no "undefined" entries on that list.