It was stocking experience when I had same issues years back, and now surprise to see that those issues are still exist without any fixes in spite of reporting long back.
Can you please confirm us that your web store developers ever written these test cases?
1. Check existing subscription before making new transaction against that customer?
2. If not, and if new payment transaction is made, then do you mark that subscription against that customer as paid?
3. While making second payment transaction, do you check any existing subscription / transaction already exist against the same customer?
4. What is causing the extra delay while making second payment transaction?
4. Assume second payment transaction went fine, but do you trigger a validation process to check potential refunds?
5. If needs to be refunded, why it can't be done instantaneously instead of delaying at random times?
[My recent cases]
6. The payment went fine (flow) for a fixed price item, and user got charged, but the API on the same payment popup says "Transaction failed". Is this fixed?
7. The payment went fine and API on popup gave correct status as paid, but later, the same API in the background script giving "Transaction failed" status. Is this fixed?
Whether one agrees or not, your team of product managers, architects, designers, and coders are really not doing a decent job of handling these issues since years without stability, timelines, quality, and especially the unpredictable review process.
If you haven't realized yet, too many developers are migrating theirs extensions and apps to Edge, Firefox, and other platforms.
Good luck to everyone, and definitely not a happy holidays for developers with these issues!!