Done Mega Magearna shouldn't appear in Random Battles

[syfuul]

What type of bug are you reporting? Random Battles

What is the bug?
when playing gen 7 random battles i used twinkle tackle (the fairy type z-move) with magearna, after using it she transformed into mega magearna even though she didn't have a mega stone and it was the wrong gen

here's the replay https://play.pokemonshowdown.com/battle-gen7randombattle-2498233559

Are you able to replicate it? If so, how?
no

Hydrametr0nice: https://replay.pokemonshowdown.com/gen7randombattle-2498233559

 

[Chains of Markov]

Pending fix:
https://github.com/smogon/pokemon-showdown/pull/11615