importing large fbx grid losing materials

i'm importing a large grid of boxes from 3ds max using fbx. Each box has its own material. When I import the boxes they come in grouped but the materials seem to get lost.

If i export a single box from the grid as an fbx file there is no problem and the material comes in, but the grouping in the large grid seems to be causing some kind of a problem with importing the materials and textures.

If i select seven of the boxes and export selected as fbx, the boxes in unity all show up with the same material/texture, which is also not correct.

I'm using the 2019 LTS version of unity, and would appreciate any insights into this weirdness.

 

Does the fbx Imported back into 3ds max still have the materials like you expect?