eBay timestamps all bids at the time they are received at a server and the information is sent on to other servers, but not all bids are actually received at all servers at the same time. It takes some time for all the servers to communicate bids around the world.
If the bids were received on different servers not located near each other, it is possible that the higher bid had not propagated far enough to block the lower bid, allowing the lower bid to be accepted. Accepting a lower bid in this case has no effect on the final price or outcome of the auction, although there are situations where it could potentially make a difference.
I have seen situations where three identical bids were accepted at roughly the same time; obviously if the bids were received at the same server, the last one should have been rejected as not being at least an increment above the current bid amount, but if the servers are far enough apart, timing comes into play. If the third bid had been a penny more and still had been accepted, it would have won the auction, though technically it would not have met the minimum bid requirement.
