Sellers aren't reporting the invalid retractions when they happen. That is how yhey get away with it. You would think Ebay could keep track of it on their own, but they don't.
There are members on here who think there is nothing wrong at all with regularly retracting bids.
The most I have seen on one bidder was 646 retractions in a 6 month period. There is no reason at all that that should be allowed to continie to happen.