Transaction.Id from Product.Purchase is different from the transactionId notified by the server notification

Hi,

In an auto-renewable subscription scenario, I receive a transaction from Product.Purchase and then send the transaction ID (e.g., 500000000738201) to my API server. After receiving the response, I called transaction.finish().

The account has purchased the subscription before and expired. So it's re-subscribe.

And then, I received a RESUBSCRIBE notification from Apple’s server to my API server. I noticed a discrepancy where the transaction ID in the notification is decreased by one (e.g., 500000000738200 instead of 500000000738201).

I’m wondering why this discrepancy occurs and how it happens.

Best regards, RoyHuang