PathTracing Render squared

Hi everyone,
I have a problem when I render in Path Tracing a cloth animation.

I created a animation in Blender ( a cloth moving on a car for an unveiling) and imported as alembic.

When I render in Lumen it is all ok:

But when I render in Path Tracing the cloth appears all squared:

Do you know how fix it?
Thank you

That looks like an edge terminator problem, which is where the PT is so accurate that it’s showing off problems with your lighting. The UE pathtracer documentation has some tips for dealing with it, but one good option if you’re rendering for offline is simply to crank the geometric density up until the terminator problem is less of an issue. You might also want to look at your normal maps or the import settings of your geo to see if there are any problems there.