Is there even an appropriate option to use?
I just read https://itch.io/docs/creators/download-keys and nowhere is it stated that unclaimable keys are a thing.
If only one key was used to be printed as a qr code, how should this even work? Not by keys to my reading of the faq.
A download key’s URL is unique and should not be shared.
I would imagine the developer wanted to share a link to a restricted page or something like that. This would be possible with one qr code for all.
When you create a download key in the Itch dashboard, at the bottom you have an option that allows you to indicate whether the key can be claimed by an Itch account or not.
Download key can be claimed — Enables anyone with an itch.io account to take ownership of the download key, preventing anyone else from using it.
It is implicitly understood that if the option is NOT checked, the key could NOT be claimed and could be used by anyone who has the URL and I assume that was the author's intention (I have no additional information other than what is written here).
I don't know if this is something allowed by Itch (the download key generation rules don't explain it anywhere). But if it were prohibited, it would be expected that this option would not exist and it would be mandatory to redeem the key.
I don't know if this is a bug of the original author or if it is indeed a bug of Itch, but since it seems to be something that is affecting several people, it is best to point them in the direction where they could get help.
Edit:
Personally, I think the best option would have been to create one key per game, have a set of stickers printed (many printing companies do this) and thus have only one download key per game. But this is just a personal opinion.
Sounds like the faq could use some work.
Something like non-claimable keys are not mentioned there. Explanation of such a use case is what I would expect from the faq, as it is bound to create confusion.
If it previously worked, maybe the key was flagged for "supicous" behaviour...
The faq is not very clear if keys are supposed to be share-able. What with the bulk keys, it rather reads like they are not share-able and the dev can even manually revoke them, if used for downloading too often.
