Restore purchases stopped working on macOS Catalina (Sandbox)

Hello,

Environment
macOS Catalina 10.15.6
Xcode 11.6, Xcode 12 beta 6
App Sandbox

Problem: A call to SKPaymentQueue.default().restoreCompletedTransactions() suddenly stopped calling paymentQueue(:updatedTransactions:) and directly invokes paymentQueueRestoreCompletedTransactionsFinished(:)

I have an unreleased Mac app with a few non-consumables, and one of the IAP has Apple hosted content.

Until a few days ago, both the in-app purchases & restore purchases were working fine, paymentQueue(:updatedTransactions:) was called during purchase and as well as restore flow, and the content was successfully downloaded.

With no code changes to StoreKit flow, the restore purchases stopped working and paymentQueue(:updatedTransactions:) is no longer called. Now, it goes straight to paymentQueueRestoreCompletedTransactionsFinished(_:).

Code Block swift
    func paymentQueueRestoreCompletedTransactionsFinished(_ queue: SKPaymentQueue) {        
        if (queue.transactions.count == 0) {
            #if DEBUG
            print ("zero restore transactions")
            #endif
        }
       ...
    }

I have looked into other forum questions, stack overflow, TN2413, and of course the documentation. Unfortunately, the problem persists.

I've filed FB8560139.

The only change I remember doing in the last few days is to install the macOS 10.15.6 supplemental update.

Appreciate any help!

Thanks