Quick in-app consumables recovery

I am making my first In-App purchase and the strange behavior is that the consumer product is being restored instead of creating a new transaction.

I followed tuto https://www.raywenderlich.com/122144/in-app-purchase-tutorial

I found an elegant approach.

here is my StoreKit helper:

import StoreKit

public typealias ProductIdentifier = String

public typealias ProductsRequestCompletionHandler = (_ success: Bool, _ products: [SKProduct]?) -> ()



open class IAPHelper : NSObject  {
    fileprivate let productIdentifiers: Set<ProductIdentifier>
    fileprivate var purchasedProductIdentifiers: Set<ProductIdentifier> = Set()
    fileprivate var productsRequest: SKProductsRequest?
    fileprivate var productsRequestCompletionHandler: ProductsRequestCompletionHandler?

    static let IAPHelperPurchaseNotification = "IAPHelperPurchaseNotification"

    public init(productIds: Set<ProductIdentifier>) {
        productIdentifiers = productIds
        super.init()
        SKPaymentQueue.default().add(self)
    }
}

// MARK: - StoreKit API

extension IAPHelper {

    public func requestProducts(_ completionHandler: @escaping ProductsRequestCompletionHandler) {
        productsRequest?.cancel()
        productsRequestCompletionHandler = completionHandler

        productsRequest = SKProductsRequest(productIdentifiers: productIdentifiers)
        productsRequest!.delegate = self
        productsRequest!.start()
    }

    public func buyProduct(_ product: SKProduct) {
        print("Buying \(product.productIdentifier)...")
        let payment = SKPayment(product: product)
        SKPaymentQueue.default().add(payment)
    }

    public func isProductPurchased(_ productIdentifier: ProductIdentifier) -> Bool {
        return purchasedProductIdentifiers.contains(productIdentifier)
    }

    public class func canMakePayments() -> Bool {
        return SKPaymentQueue.canMakePayments()
    }

    public func restorePurchases() {
        SKPaymentQueue.default().restoreCompletedTransactions()
    }
}

// MARK: - SKProductsRequestDelegate

extension IAPHelper: SKProductsRequestDelegate {

    public func productsRequest(_ request: SKProductsRequest, didReceive response: SKProductsResponse) {
        print("Loaded list of products...")
        let products = response.products
        productsRequestCompletionHandler?(true, products)
        clearRequestAndHandler()

        for p in products {
            print("Found product: \(p.productIdentifier) \(p.localizedTitle) \(p.price.floatValue)")
        }
    }

    public func request(_ request: SKRequest, didFailWithError error: Error) {
        print("Failed to load list of products.")
        print("Error: \(error.localizedDescription)")
        productsRequestCompletionHandler?(false, nil)
        clearRequestAndHandler()
    }

    private func clearRequestAndHandler() {
        productsRequest = nil
        productsRequestCompletionHandler = nil
    }
}

// MARK: - SKPaymentTransactionObserver

extension IAPHelper: SKPaymentTransactionObserver {

    public func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
        for transaction in transactions {
            switch (transaction.transactionState) {
            case .purchased:
                complete(transaction: transaction)
                break
            case .failed:
                fail(transaction: transaction)
                break
            case .restored:
                restore(transaction: transaction)
                break
            case .deferred:
                break
            case .purchasing:
                break
            }
        }
    }

    private func complete(transaction: SKPaymentTransaction) {
        print("complete...")
        validateReceipt()
        deliverPurchaseNotificationFor(identifier: transaction.payment.productIdentifier)
        SKPaymentQueue.default().finishTransaction(transaction)
    }

    private func restore(transaction: SKPaymentTransaction) {
        guard let productIdentifier = transaction.original?.payment.productIdentifier else { return }

        print("restore... \(productIdentifier)")
        deliverPurchaseNotificationFor(identifier: productIdentifier)
        SKPaymentQueue.default().finishTransaction(transaction)
    }

    private func fail(transaction: SKPaymentTransaction) {
        print("fail...")
        if let transactionError = transaction.error as? NSError {
            if transactionError.code != SKError.paymentCancelled.rawValue {
                print("Transaction Error: \(transaction.error?.localizedDescription)")
            }
        }

        SKPaymentQueue.default().finishTransaction(transaction)
    }

    private func deliverPurchaseNotificationFor(identifier: String?) {
        guard let identifier = identifier else { return }

        purchasedProductIdentifiers.insert(identifier)
        UserDefaults.standard.set(true, forKey: identifier)
        UserDefaults.standard.synchronize()
        NotificationCenter.default.post(name: NSNotification.Name(rawValue: IAPHelper.IAPHelperPurchaseNotification), object: identifier)
    }
}

      

        
        
        
      

    

I can buy once, the second - automatically:

This In-App purchase has already been purchased. It will be restored for free

When I receive this message, none of the IAPHelper methods are called.

My iTunes shows it is consumed:

Even uninstalling the purchased app is still restored.

This really looks like Apple's bug, as my first tests I could buy 2.3 times without this message.

If this is not a bug, how can I prevent this situation?