My poke faints for no reason at all

[Sghir]

hello, i want to report a bug that makes my haxorus faint for no reason.

this happened for the 4th time, and everytime it was when i was almost to cerulean cave or just when i enter, and a pokemon spawns.

it said my monferno (second poke in party) fainted, and it was my haxorus (first poke in party) who fainted.

i sent it to battle, it appeared, but i couldnt use any move.

called it back and sent another pokemon, and then it showed it was really fainted.

i have provided some screenshots, but i didnt make a video since the bug seem to happen randomly (ive unlocked cerulean cave not long ago)

hope i explained everything, and that ull find a solution to this. it never happened to me, and this happens only at the location i said before[ATTACH=full]41333[/ATTACH]