rectangular groom flickering / glitching

Hi.

I’d like to ask, does someone had ever before a flicker like this on groom?

https://youtu.be/x8l74zOQusY

I tried everything.

In irectional light and skylight, enabled ‘cast deep shadow,’ and enabled the contact shadow length in world space units

I used following Console Variables in movie render queue:

r.HairStrands.Voxelization.Virtual.VoxelWorldSize 0,07
r.HairStrands.Voxelization.Raymarching.SteppingScale 1
r.HairStrands.Voxelization.Virtual.VoxelPageCountPerDim 16
r.HairStrands.DeepShadow.SuperSampling 1

I used those CV in various tries.

And this glitching / flickering is only disappear while I completely disable cast shadows from groom component. But then it doesnt look so good.

do you guys have any idea, what i can try next?

thank you and cheers