Hey @Martin W!
I took a look into our database, and I can definitely confirm on our end that we have users with receipts that are being shared with family members for your app- so it looks like things are working as expected, which is a really good start.
Apple has indicated that it can take up to an hour after a purchase for it to be available for family members, but it's best to expect maybe a couple of hours. The user that wants access (the family member) should then 'restore purchases' to sync the receipt to our backend.
Ultimately, it’s tough to tell on our end what is happening since we don’t have much insight into whether or not family sharing is working until we actually receive the transaction in the user’s receipt. Has this user confirmed that they are indeed part of the family member’s iCloud Family? It may be a misunderstanding on the user’s end about how family sharing works.
Edit:
We weren’t able to figure out why this particular user wasn’t able to restore family purchases, but other users were. If anyone else is having issues, please reach out to support and we’d be happy to look into this further.