We are facing an issue where VoIP notifications are not delivered to a user's device.
If we login with the user credentials on another device the VoIP notifications are being received, if he logs in on his device VoIP notifications are not being received anymore on all devices.
So When the user logs in on the affected device, all devices on that account stop receiving VoIP pushes (including the affected one). Logging out on the affected device restores delivery to other devices.
What could cause this issue?
It's only happening for this user so the configuration and mobile app PushKit code is working as intended.