Hello,
I'm using Apple Wallet passes with a custom backend for distributing and updating them, as described in the documentation (https://developer.apple.com/documentation/walletpasses).
I'm sometimes seeing a behaviour where the device does not download an updated pass even though the push notification for informing about the changes has been successfully sent (I've received a success response from APNs).
APNs documentation says that it should retry sending the notification if the device is not reachable, but in the cases I'm describing here, the request from the device to fetch the updated pass never arrives. I don't have the apns-expiration header set. Also, I've checked the load balancer and firewall logs, etc. and there are no traces of the requests.
Any thoughts on what might be the issue here? Or how to debug this further?