UDIM with external texture files

Hi! I coding 3D-Coat applink and I try to make udim support for it. The problem is that when I attach my texture_1001.jpg into texture node. It only shows first tile in preview view. The second is pink. Both textures files are in same folder. Is this know problem? There is picture how it looks in 3d-coat and also results in blender

here are the files if someone wants to try.

testscene.zip (109.3 KB)

Using latest 2.90 daily build