The rival did not bid after you. They had already placed a higher maximum bid before your snipe.
When your bid went in, eBay’s proxy system raised their bid instantly.
Example: if they entered $1,000 a day earlier and you entered $598 in the last second, eBay would record your $598, then outbid you by one increment. The rival wins at just over $600.
This is how eBay’s system has always worked. Sniping only hides your interest; it cannot overcome a higher maximum bid.
bidslammer