Can not access a directly connected device on a link SOHO marked down

I have a mobile application of the SOHO Mk3. I just updated to the latest firmware 8.0.2.

My configuration includes a Ethernet connected Ubuquity Bullet 5 router mounted outside my motorhome. When I move to a new location I need to access this router to select a new connection and I would like to do it from a computer connected to the WIFI supplied by the SOHO.

It works fine if I turn off interface testing on the SOHO. When I turn on interface testing using DNS query and I drive away from the working location, the SOHO marks the interface down as it should and switches to the next interface in the list which is my Verizon hotspot.

The problem occurs when I arrive at a new location and wish to access the Bullet which is now on a link that is marked down.

I understand the SOHO is not supposed to route packets to a downed interface, but the interface itself is not down only the downstream system is down.

1 - Why can I not access a directly connected device.
2 - Is there some way to make this work?

Without this capability the fail soft system of the SOHO is mostly worthless as I have to turn off testing of the connection to get access to the downstream router and restart the connection. Turn off testing, make the connection, turn on testing is a lot of work for as system that is supposed to be automatic.

Any help would be appreciated.