Hi, I released my game 6 months ago using Unity 5.4. It was a freemium model where you get a free demo but can buy the rest of the game via a single non-consumable IAP transaction. This has worked flawlesly ever since.
I have update it to 5.6 with a lot of nice extra features etc… and for some reason every new version I upload (to the beta track) says I dont have the levels package and displays the purchasing button… and what is worse it works and allows me to buy the product again!
Once bought it works perfectly, and even reinstalling the app restores the purchase… until I update a new version to the Beta track :S
The item is marked as ProductType.NonConsumable in the Builder.