I had a puzzling incident that happened earlier than when compared to yours makes more sense. I had a cursed Keeper and my opponent played 2 ravines. I expected I'd have a 4/1 damaged abomination at the round start but instead it was a healthy 4/3. It seems like they both resolved at the same time so the 1/1 effectively just took 4 damage. That gets confusing because I also know that the order of a ravine and landmark that summons a unit, like an ancient prep or frozen tomb DOES matter. The one on the left resolves first so you'll either get a healthy or damaged unit depending on order. It seems like there's some sort of nested heirarchy. All round start effects resolve before everything else, even their effects on units, but in their step there is an order to what's happening. It seems like the game doesn't check at all who wins or loses during that step so as far as the game is concerned you both died by the time the round start effects ended. That in itself is confusing because the game DOES check an order of some sort for round end effects like you can see in Star Spring mirrors or leviathan mirrors. Maybe it checks after all of one player's effects have completed but not after each individual one? That would be consistent with the tie you had and the round end scenarios I listed. I have no idea.