Hey Fez... Welcome to the forum... overbidding has been discussed here several times, but to make it short, there are some people out there that over bid and help CI's profit margins. So let them overbid!!
However, some people mean to put thier bids on auto bid and hit the wrong button and accidentally put the wrong bid in, I did it the second time I bid on a lot. I think you can now edit your bids, so we will see if the overbidder corrects his error!