Pixel block shadows on cloth

Hurdy3D

Hey,

today I discovered this promo image:

 

On the orange top is some shadow with loocks very unnatural (pixel blocks/artefacts).

I have images where I had also this issues with some clothes, but I didn't find any solution for this.

Any idea what's the cause and how to fix it?

Linwelly

Looks liek the subdivision of the top could have been higher. Generally this happens when the light comes at a very low angle in regard to the surface and there are hard shadows.Setting the pixel filter raduis lower will help some but sometimes it can't be avoided completely