I walk in the overworld, when sometimes I hear a creeper or a ghast for no reason.

Biome : Lavender

Optifine : Yes

Alright, I was scared of my game, sorry and thank you <3

I'm sorry, I don't quite follow.
Is the issue resolved or does the modpack have a malfunction?

I don't know how this is possible, but this problem is no longer present. If he comes back I will contact you directly

I supposed the isses was resolved

I think this is due to corruption from Forbidden and Arcanus. If you kill enough passive animals, it will grant you some debilitating effects.