I have the same problem with a pair of goggles I downloaded that were cloned from the OFB scuba goggles.
I can put them on fine in CAS but when I get an adult sim to change their appearance in a mirror, the goggles show up has messed up recolors of the OFB goggles instead of the custom meshes, and it's not just the thumbnails, it shows up messed up in game. So the goggles pretty much only work on CAS sims that were made with the goggles on. I just thought the creator messed up when creating the meshes.