John S. wrote:

I believe the second bidders bid becomes recognized by Ebay only if the
seller cancels the high bid.

Partially correct--but there's more than just "canceling": could be he
is a deadbeat bidder who won't/can't pay, is an actual shill who had no
intention of paying, says he bid wrong item (or wrong amount), dies
before he can send the payment, buyer's regret...there are no end of
real (or bogus) reasons that would allow the second highest bidder to
kick in...