Error with Grist, the Plague Swarm

[Treacheres]

[[Grist, the Plague Swarm]] can't use the -6 loyalty ability to restore [[Tergrid, God of Fright]].

///

Error type: SERVER - game error

Client version: 1.4.56-V3 (build: 2025-02-09 16:02)
Java version: 1.8.0_201
Default charset: UTF-8

Game error occurred:

java.lang.IllegalArgumentException: Wrong code usage: can't create permanent card from split or mdf: Tergrid, God of Fright
Server version: 1.4.56-V3 (build: 2025-02-09 16:02)
Stack trace:
mage.game.permanent.PermanentCard.(PermanentCard.java:64)
mage.cards.g.GristThePlagueSwarmMinus6Effect.apply(GristThePlagueSwarm.java:155)
mage.abilities.AbilityImpl.resolveMode(AbilityImpl.java:226)
mage.abilities.AbilityImpl.resolve(AbilityImpl.java:213)
mage.game.stack.StackAbility.resolve(StackAbility.java:85)
mage.game.GameImpl.resolve(GameImpl.java:1815)
mage.game.GameImpl.playPriority(GameImpl.java:1738)
mage.game.turn.Step.priority(Step.java:73)
mage.game.turn.Phase.playStep(Phase.java:205)
mage.game.turn.Phase.play(Phase.java:91)
mage.game.turn.Turn.play(Turn.java:141)
mage.game.GameImpl.playTurn(GameImpl.java:1157)
mage.game.GameImpl.play(GameImpl.java:1064)
mage.game.GameImpl.start(GameImpl.java:1040)
mage.server.game.GameWorker.call(GameWorker.java:35)
mage.server.game.GameWorker.call(GameWorker.java:16)
java.util.concurrent.FutureTask.run(FutureTask.java:266)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
java.lang.Thread.run(Thread.java:748)

[github-actions]

Grist, Voracious Larva // Grist, the Plague Swarm - (Gatherer) (Scryfall) (EDHREC)

{G}
Legendary Creature — Insect
1/2
Deathtouch
Whenever Grist, Voracious Larva or another creature you control enters, if it entered from your graveyard or you cast it from your graveyard, you may pay {G}. If you do, exile Grist, then return it to the battlefield transformed under its owner's control.
🔄
Legendary Planeswalker — Grist
3
+1: Create a 1/1 black and green Insect creature token, then mill two cards. Put a deathtouch counter on the token if a black card was milled this way.
−2: Destroy target artifact or enchantment.
−6: For each creature card in your graveyard, create a token that's a copy of it, except it's a 1/1 black and green Insect.

Tergrid, God of Fright // Tergrid's Lantern - (Gatherer) (Scryfall) (EDHREC)

{3}{B}{B}
Legendary Creature — God
4/5
Menace
Whenever an opponent sacrifices a nontoken permanent or discards a permanent card, you may put that card from a graveyard onto the battlefield under your control.
🔄
{3}{B}
Legendary Artifact
{T}: Target player loses 3 life unless they sacrifice a nonland permanent of their choice or discard a card.
{3}{B}: Untap Tergrid's Lantern.