3D Indexing not working in Navigation Experience

When I open an assembly with Product Finder & Navigation Experience, I get a message that 3D thumbnails are not available yet. The geometry will then load but I am unable to create a volume filter and I get a message that the object is not indexed. This does not occur when working in Product Finder Classic. Is this a current limitation of Navigation Experience? Is there a work around to ensure indexing/ 3D thumbnails are generated? Thanks!