When you see your posted/current bid is lower than the Maximum Bid you entered, it is because AutoBid placed a bid on your behalf which was lower than your Maximum Bid.
When you place a bid, you are entering the maximum amount you are willing to pay for an item. AutoBid bids on your behalf, and always bids the least it can to win the auction.
When you are outbid, AutoBid raises its bid, but it never bids more than your maximum bid.