FortiExtender DNS broken

FortiExtender used with SD-WAN

FortiExenter adds the Cell provider DNS server to the Fortigate's DNS servers.

DNS queries now fail whenever cell providers DNS server is used, and the DNS traffic originates from the other primary internet link WAN1.

Cell provider will only answer DNS queries from its network.

Fortigate WAN2 GUI has an option to not override internal DNS.

FortiExtender does not.

The workaround at the moment is adding a route to the cell DNS server to the FortiExtender.

Which works until the cell provider serves up a different DNS server IP to use.