Game crashes when AI plays a card with cost {X} and that targets a player, this cards can be coded around that restriction and still work as per the rules.
The BIGGEST BUG the game has now is that crashes occur when a PERMANENT TARGETS A SPELL IN THE STACK, sometimes the AI can make this cards work (WTH!?) but never the player.
Effects like mirari and similar could be coded so that you don't target the spell but trigger and copy the source of the trigger, look at the code of mirari for this to be more clear.
This effect used to work for many many years I remember Glen Elendra Archmage being one of my favorite cards back in the day. This bug has been present since god knows when, as early as october 2016: https://wololo.net/forum/viewtopic.php?f=4&t=66296&start=150#p98160
Also freaking Lemures caused the AI to just keep repeating the effect so I put a limit on activations on them.
RNA Guild Kit Set Code: GK2
Ravnica Allegiance Set Code: RNA
Ultimate Box Topper Set Code: PUMA
Ultimate Masters Set Code: UMA
GRN Guild Kit Set Code: GK1
Guilds of Ravnica Set Code: GRN
Commander 2018 Set Code: C18
Core Set 2019 Set Code: M19
Signature
Spellbook: Jace Set Code: SS1
Battlebond Set Code: BBD
Commander Anthology
Volume II Set Code: CM2
Dominaria Set Code: DOM
Duel Decks: Elves
vs. Inventors Set Code: DDU
Masters 25 Set Code: A25
Rivals of Ixalan Set Code: RIX
Unstable Set Code: UST
Explorers of Ixalan Set Code: E02
From the Vault:
Transform Set Code: V17
Iconic Masters Set Code: IMA
Duel Decks: Merfolk
vs. Goblins Set Code: DDT
Ixalan Set Code: XLN
Commander 2017 Set Code: C17
Hour of Devastation Set Code: HOU
Archenemy: Nicol
Bolas Set Code: E01
Commander Anthology Set Code: CMA
Amonkhet Set Code: AKH
Amonkhet
Invocations Set Code: MP2
Duel Decks: Mind
vs. Might Set Code: DDS
Modern Masters 2017 Set Code: MM3
