Same issue! Using an old sandbox account. All of a sudden iaps are broken. And I can't download apps, or get an iaps when the device is in this state. I thought production was down..
Background Task 14 ("SKProductsRequest"), was created over 30 seconds ago. In applications running in the background, this creates a risk of termination. Remember to call UIApplication.endBackgroundTask(_:) for your task in a timely manner to avoid this.