"Don't know" names added to my Imported contacts list

This morning I found a LOT of new names on my Imported Contacts list. I don't know where all of them came from, but I did notice that all of the people that rejected my previous invitations, flagging them with "Don't Know" (even though they do know me, because there is no other option to decline an invitation), have suddenly shown up on this list.

Why add people who have already refused an invitation to my list of people to invite? THis is a BUG!