DroneCAN Moving Baseline GPS not detected on boot

Cube Black, ArduRover 4.1.5

Trying to use Moving Baseline with Ardusimple F9P GPS units, with the 2nd GPS connected via DroneCAN (same result with mRo CAN Node F303 or mRo KitCAN as the CAN adapter).
The GPS is not detected on boot (2nd GPS is not shown in the Mission Planner data screen).

If both GPS’ are connected to directly to GPS1 + GPS2 (No CAN), both units are detected on boot.
(GPS_TYPE = 17, GPS_TYPE2 = 18)

If GPS1 is set to uBlox-MovingBaseline-Base + 2nd GPS is set to DroneCAN-MovingBaseline-Rover, the DroneCAN unit fails to be detected.
(GPS_TYPE = 17, GPS_TYPE2 = 23)

Switching them around so GPS1 is uBlox-MovingBaseline-Rover and GPS2 is DroneCAN-MovingBaseline-Base also fails to be detected.
(GPS_TYPE = 18, GPS_TYPE2 = 22)

However, if GPS1 is set to uBlox-MovingBaseline-Base + 2nd GPS is set to DroneCAN, the DroneCAN GPS is detected (We see the 2nd GPS in Mission Planner).
(GPS_TYPE = 17, GPS_TYPE2 = 9)

After the 2nd GPS is detected this way, it can be changed back to DroneCAN-MovingBaseline-Rover (GPS_TYPE2 = 23) and it remains detected until next reboot.

Any tips on how to configure this properly would be greatly apprecaited.