There are two circ*mstances where placing a new bid while you are the current high bidder can cause the "current bid" to go up immediately. In neither case are you bidding against yourself:
1. If it is "Reserve not met" and the new bid is high enough to meet the reserve, the current bid goes up to the exact amount of the Reserve Price without need of another bidder. You are not bidding against yourself, you are bidding against the Reserve Price which you must meet to win.
2. If you are in the lead by less than a full increment (including having an earlier-placed tying amount--if you have lost the tie because you bid was later than the other bid for the same amount it WILL go up to 1 increment over the tie amount) the current bid might go up to the full increment over the underbidder's maximum bid when you place a new bid. You are not bidding against yourself, you are bidding against the underbidder (the question being WHICH of your bids is used in calculating the price) and the general rule is that the price is 1 increment more than the underbidder's maximum bid. Then if there are no new bids by anyone except you before the end, the price might (most likely--I've never seen it not do so since 2011) go down to the amount of the earlier bid after the end. This is a long story that has to do with a class action suit about a decade ago.
