When a player or a mob is in a minecart that drives over an activator rail that is powered by redstone, it will drop the player 1-2 blocks behind the activator rail, instead of dropping the player on the right side of the rail, as it says in the wiki. This happened in a realm, so it might have something to do with server timings/lag. If it is something else than a bug, please tell me what it is because it drives me crazy.