There was definitely sync bugs with replays at various points. There was even desync bugs even in live multiplayer games; there was detection that it desynced

There was definitely sync bugs with replays at various points. There was even desync bugs even in live multiplayer games; there was detection that it desynced which would end the game, which in turn meant exploits that would intentionally cause a desync (which would typically involve cancelled zerg buildings for some reason).