iOS Storekit stuck on "Purchasing" (Prime31)

I have a subscription model system that I'm setting up. I am using a receipt validation system which passes the 64bit encoded receipt from a transaction to the iTunes server and I receive a JSON string detailing the interaction. All of the information in the result appears correct. But the original receipt still shows "Purchasing" as the transaction state. Is this expected?

On the device, in sandbox mode, I am able to create a completed transaction, confirming the purchase. I can see the output in Xcode telling me that the transaction was successful. And I have the new receipt in the app's Document's folder. I can access the receipt(s) using StoreKitBinding.getAllSavedTransactions(); When I get the transactionState for each receipt they all show up as "Purchasing". I'm assuming that this is not correct. The proper state should be "Purchased" I think.

Is there an additional step that needs to be done? I initiate the purchase with StoreKitBinding.purchaseProduct(); The StoreKitManager.purchaseSuccessfulEvent function calls StoreKitBinding.finishPendingTransaction(transactionId)

I can't see anything in the docs to imply that I need to do anything different.

The items to be purchased are auto-subscriptions, so maybe the state is supposed to be "Purchasing" all the time and I'm all set. I can't find any good docs for this specific situation.