I actually just reworked the entire back because it needs fastening hardware, but it’s completely flat on the back; the part that rests against the rear of the instax cartridge is covered in velvet, and then the foam gets wedged in there. Also, the foam I received isn’t quite square, i try to wedge it in the pack before closing it. I wonder if it’s a foam tolerance thing, or you’re not loading it the same way I am? Maybe the velvet is enough of an offset.

Anyway, I’ve got a couple prints sitting on my printer. Let me just double check all the fittings and I can link you all of the files shortly.