VoIP Registration Fails after WAN Down/UP

I have an intermittent issue with a few of our Balance 30 LTE devices. It seems to occur after WAN 1 Health Check fails and recovers. When I run a capture the Balance 30 is not sending any SIP messages from the WAN but are receiving from the devices. This also has occurred on multiple VoIP Providers. Has anyone seen this or have suggestions to what could be the cause? I have opened a ticket but I can’t reproduce on demand so I never get anywhere.

Do you have terminate sessions on link recovery ticked on the outbound priority policy?

I do have that checked on ones that have failover. I have seen this issue for a few that don’t have any backup WAN or outbound Policy.