UDIM one material element instead of multiple elements

I’m importing a photoscanned mesh with 3df Zephyr in Unreal 5.5 (the same for 5.4).

When the mesh is imported (obj or FBX with multiple UDIM textures) the mesh has multiple material elements (each one with it’s own UDIM VT texture) instead of one material with the first VT texture applied (that is linked to the others).

Do I need some particular settings when importing or this is related to how I’ve exported the mesh?