Materials Added to an FBX Will Not Be Added When Reimporting

Adding a material to an FBX with a Multi/Sub-object material, then reimporting the FBX will not import the new material. The material element will be added to the mesh but the material applied will not be imported. 

The issue does not occur if you delete the imported items and then import it again.

Video of the issue:
[Link Removed]

Found in 4.18 CL# 3832480, 4.19 CL# 4033788, 4.20 CL# 4369336, 4.21 CL# 4489857, and 4.22 CL# 4498653

1. Open the attached 3DS Max file and export the FBX
2. Open the editor and import the FBX
3. In 3DS Max Add an additional material ID slot to its multi/sub object material and set one of the green faces to ID 6
4. Apply a material to the ID 6
5. Export the FBX again
6. Right click on the mesh in the Editor and select reimport

Results:
The material added to the multi/sub-object material will not be imported along with the changes with the mesh. Additionally the menu that appears upon reimporting doesn't seem to give much context.

Expected:
The material added to the multi/sub-object would be imported.