iOS 13 Background push throttled after reboot

I'm implementing the new background push notification system with:

• apn-push-type=background
• apns-priority=5

in the request header. If I close the app the notification is delivered and the device doesn't throttle it (as per documentatiuon we can use few of this push or the device throttle them not forwarding them to the app). If i force quit the app the app awakens and process the push notification.

After a reboot the notification is throttled and there is no way to make the app receive it. Is there something more I should add to my notification payload or header? Currently the payload is like

{
    "aps":{
        "content-available": 1
    }
    ... // other data which the app process
}