3Dsmax multi-material can NOT show the bitmap

The problem show in this video
https://youtu.be/uxZlVnA2k9s

Just so so so simple I want a pillar with two map

The BUG is after exported USD and MDL to OMN
multi-material can use 1 map only, not showing another map

if future project has many mapping in a poly, what can I do?