I've gotten multiple win notifications in a row, with the win count also incrementing more than once. it seemed to happen whenever a multi-trigger card triggered the win.
On a semi-related note, the player starts their next turn before the opponent actually ends theirs. It was also the case in previous versions, but the multi-trigger cards make it more apparent. there was one game I thought I was going to win by shrinking the opponent, except they hadn't finished their turn yet, so they were able to grow back above 1ft just before the win check could register that they went under it