Bugged balancers ?

I just defeated the boss after changing the shifting earth (im too stupid to understand the shit i have to do and i need to sleep) back to the boss, the main issue is that for a portion of the fight the ai of the enemies just broke , i dont know if thats the idea "balance" as most valkries will stand still not reacting to anything like literally while a few attack or its just bugged ... either way drop any hints for the new shifting earth that could help