Hello! There's definitely something odd happening in this case, but I'm at a loss as to what it could be. The only thing we can do on the backend is turning key distribution on and off and add more if we're running out, so I'm afraid there isn't a lot we can do directly. If you scroll to the bottom of this page, you'll see Itchio does have a small section on why you might not be receiving a key despite it being included, though none of the main reasons should apply to us (we're not participating in a major charity bundle at the moment, and we still have plenty of keys left to redeem in the system).
The best suggestion I can offer is to follow Itchio's directions and reach out to support (there's a link to the support page in the FAQ I linked before). They're in a better position to answer your question at the moment.