Here'a what I think happened: Jed was fired at the end of season 20 and was not supposed to return for season 21. Meghan was going to replace her.
However, Meghan's deal wasn't done in time for the start of season 21, so Jed was a placefiller until they got Meghan's deal done.
This is the only reason of why they would get rid of a cohost 3 weeks into the new season.