Maybe Jinzo ended up with even less health than you but your HP reached 0 because of the same action, so that's a tie. It definitely works like this. Plus, the IA does not care if you are conceding when the match is technically already over. Try to play Mill Rogue against the Innkeeper, then concede right after you have played the lethal Oracle. It will still be counted as a win, even if the animations are not over yet.
Maybe Jinzo ended up with even less health than you but your HP reached 0 because of the same action, so that's a tie. It definitely works like this. Plus, the IA does not care if you are conceding when the match is technically already over. Try to play Mill Rogue against the Innkeeper, then concede right after you have played the lethal Oracle. It will still be counted as a win, even if the animations are not over yet.