i also encountered this issue tonight during my playthrough, unfortunately. i have a VOD here where it happens at ~54:45
have you had any luck with figuring out a possible fix?
This seems to be a 1/100 players sort of bug. I have no idea what causes it, and can't seem to reproduce it; as far as I can tell, it's a problem with the way this version of unity runs on particular systems.
I think editing the card into your inventory manually (following the above instructions) is your best bet for now. If I still can't locate the bug, I might make a patcher that adds the card to your inventory while I'm putting together a demo for IGF. It would just do the same thing as a manual inventory edit, though.
Sincere apologies for the inconvenience—hate to be one of those "here's an arcane registry hack to fix your issue" devs.