Regarding the interaction between Bloodletter of Aclazotz and Fraying Omnipotence.

[stormcat664]

Describe the bug
When Bloodletter of Aclazotz is on the battlefield, I cast Fraying Omnipotence. If I sacrifice Bloodletter of Aclazotz during the resolution of this spell, based on the order of the card text, the opponent's life total should become 0; however, this does not happen in Forge.

To Reproduce
Steps to reproduce the behavior:

1. Bloodletter of Aclazotz in the battlefield
2. Cast Fraying Omnipotence and sacrifice Bloodletter of Aclazotz
3. See error

Expected behavior
Opponent's life total should become 0.

[kojotak]

According to https://scryfall.com/card/m19/97/fraying-omnipotence

When Fraying Omnipotence resolves, first each player loses the appropriate amount of life at once. Next, the player whose turn it is chooses an appropriate number of cards in hand without revealing them, then each other player in turn order does the same, and then those cards are all discarded simultaneously. Then, the player whose turn it is chooses an appropriate number of creatures they control. Each other player in turn order does the same, knowing choices made by previous players. Finally, all of the chosen creatures are sacrificed simultaneously.

but debug shows, that there is a RepeatEachEffect for each player. So current player looses life and then sacrifices a creature. After that, an opponent looses life, but since the Bloodletter of Aclazotz is already sacrificed, the replacement effect does not pass the ReplacementEffect#zonesCheck test and the life loss is not doubled.

This can be seen even in game log: