I have an app with one subscription to buy. Buying works fine and renewal seems to work fine, too.

I am observing transaction for this IAPin the background. To understand what is happening in the background I add print debug statements and I see that after each renewal two nearly identical transactions exist. This is the function which generates the task to watch for transaction happening in the background:

private func observeTransactionUpdates() -> Task<Void, Never> {
    Task(priority: .background) { [unowned self] in
        for await verificationResult in Transaction.updates {
            await self.updatePurchasedProducts()
            if case .verified(let transaction) = verificationResult {
                print("Verified")
                print(transaction)
                await transaction.finish() // Ensure finishing all transactions
            } else if case .unverified(let transaction, _) = verificationResult {
                print("Unverified")
                print(transaction)
                await transaction.finish() // Even finish unverified transactions
            }
        }
    }
}

This is the debug output happening all 3 minutes(sandbox) after renewal:

 Verified
 {
   "bundleId" : "...app",
   "currency" : "EUR",
   "deviceVerification" : "...qZZf",
   "deviceVerificationNonce" : "...df9",
   "environment" : "Sandbox",
   "expiresDate" : 1718878102000,
   "inAppOwnershipType" : "PURCHASED",
   "originalPurchaseDate" : 1718536890000,
   "originalTransactionId" : "...1810",
   "price" : 2990,
   "productId" : "....premium.monthly",
   "purchaseDate" : 1718877922000,
   "quantity" : 1,
   "signedDate" : 1718877887210,
   "storefront" : "DEU",
   "storefrontId" : "...443",
   "subscriptionGroupIdentifier" : "...060",
   "transactionId" : "...5774",
   "transactionReason" : "RENEWAL",
   "type" : "Auto-Renewable Subscription",
   "webOrderLineItemId" : "...9876"
 }
 
 Verified
 {
   "bundleId" : "...app",
   "currency" : "EUR",
   "deviceVerification" : "...ocx",
   "deviceVerificationNonce" : "...3bf",
   "environment" : "Sandbox",
   "expiresDate" : 1718878102000,
   "inAppOwnershipType" : "PURCHASED",
   "originalPurchaseDate" : 1718536890000,
   "originalTransactionId" : "...1810",
   "price" : 2990,
   "productId" : "....premium.monthly",
   "purchaseDate" : 1718877922000,
   "quantity" : 1,
   "signedDate" : 1718877888930,
   "storefront" : "DEU",
   "storefrontId" : "...443",
   "subscriptionGroupIdentifier" : "...060",
   "transactionId" : "...5774",
   "transactionReason" : "RENEWAL",
   "type" : "Auto-Renewable Subscription",
   "webOrderLineItemId" : "...9876"
 }

After a renewal of a purchased product I would expect one transaction with a valid expiration date happening in the background but not two transactions with the same expiration date. Why is that so?