Still receiving CONSUMPTION_REQUEST after receive REFUND request

Hi, recently our system received many CONSUMPTION_REQUEST after receive REFUND request for some transaction. EX: we have one transaction wants to refund, and our system receives the first CONSUMPTION_REQUEST at 10th Oct and receives the REFUND request after two days(12th Oct), there is no CONSUMPTION_REQUEST coming between those time, and after that, we recieve many CONSUMPTION_REQUEST between 13th Otc to now. Not sure if it this is what Apple excepted, because we are not found the document related to this. Why we post this question is for our system, what we always faced is there is no CONSUMPTION_REQUEST coming after receive the REFUND request before.

If the notification failed to send the first time, you may be observing retries, which can occur after the REFUND has completed.

Thanks for the reply, is there any chance we can know if the notification failed to send the first time? And what should we do in this situation like how to stop it

Still receiving CONSUMPTION_REQUEST after receive REFUND request
 
 
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