problem with floor generator object in UE5

Hi all

sorry for my poor English.

i have a problem with the an object in my Ue5 project.

i have a rec in 3dSmax with FLOOR GENERATOR modifier and multi texture material.

when i try to import it to UE everything is fine in lit view. the mesh, the materials and everything.

but when i try to change the view mode to path tracing, some floor tiles render like a black tile with no material.

u can see the problem in this video