Landscape render messed up


I have a problem, each time I model a landscape, render is messed up and do noise only in landscapes parts as if it was clipping then I use denoise, even today it has done the same thing for a canyon rendering, any explanation ?
It’s on the little mountains

It will do the same thing each time i create an animation with mountains, rocks etc, any idea ?
I have set optix denoise and 200 samples in cycle, it sounds like there is a different denoise pattern

Problem solved, optix isn’t enough to denoise a complete animation, it needs a strong denoiser in post production as external plugin such like neat video