Sheoldred Trigger Revives Players
I've found a bug with Sheoldred, the Apocalypse. If my opponent controls Shelly and is on 2 life, if I target them with Blood Pact they will draw 2 cards and lose 2 life. Upon resolution of the spell, they are at 0 life, then the Shelly triggers go onto the stack, but this should not matter as the player is at 0 life and should lose the game on the spot as one would in paper magic.
On mtga however, the player gains 4 life and is revived somehow... not sure why this happens, but I'm hoping it is a card-specific issue and not an issue where all triggers that gain life can resolve post-mortem and bring players back up from 0. To be clear, the player did not actually die, there was no animation, but the life total was 0, then went back to 4.
I noticed another similar issue today as well. When a player has a creature with lifelink, if they are set up to take lethal damage from unblocked attackers, but have a lifelink creature in play blocking another attacker(so they would gain 1 or more life to then not die to the unblocked attackers), the health will go down to 0 before the player gains the life back to not die.
The outcome of the attack is correct and matches with what the resolution of combat damage would look like in paper magic, but the fact that it shows 0 life for a moment makes me think that the resolution to the first bug I mentioned MAY cause this to be a problem depending on how exactly the program is written to see that the player is at 0 life.