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Hi, we've observed a weird behavior for a small amount of our user that we keep receiving the same token from APNs despite it's shown as Unregistered. When we try to send push to the token, we got an Unregistered error so we remove that token from our server. However, later we would receive an add token request from the client with the same token we just removed, and when we try to send to the token it returns Unregistered again so we remove the token again. This happened 3 times for a user in an hour. The identifierForVendor remains the same for all the requests. We also owns the client and I've checked client code that it's sending the token it received from didRegisterForRemoteNotificationsWithDeviceToken to the server.