You assume wrong, I have had to work with hundreds of thousands of individual labels and also with their transferability.
As you say, there are associated problems, but since it is relatively common, there are many solutions available, including renting automatic labeling machines depending on the product format and volume. But in tests of a few thousand, we have had to label manually or outsource warehouse.
Anyway, my intention was to show alternatives that would help you, not to argue.
You are the ones who have been unable to redeem your game for a month and that is why I try to offer alternatives, but if you prefer to wait for someone solve the problem, that's fine, as you say it is your decision and from what I see, any comment is causing more irritation than helping, so I leave my part here.
EDIT:
By the way, my intention is not to have you change your system, but to consider alternatives when you see the problems that may exist.
If Leafo answers you and fixes the problem with the keys, it will obviously be the simplest and most effective solution, but because of my job, I always try to think of alternative solutions, especially when "plan A" does not depend on my resources.