This is kind of obvious when I discovered this but Import into level breaks when meshes and materials have the same name in the imported .fbx file. You can end up with meshes/materials in the content browser which actually have the same name which is kind of weird already:
but the bigger issue is that the objects that had colliding names with materials just don’t appear in the level itself and the static mesh components that are normally placed in the Import into level BP are replaced with scene components. I think Import into level should just fail if materials have colliding names with meshes.