Dolphin and Virtualhere

I'm using the Triforce fork of Dolphin with a Hori wheel, and I experience the following:

I have a raspberry Pi set up with the wheel connected via USB, and running Virtualhere server.
I have a PC running the Virtualhere client.

if I launch Dolphin from the PC, I have full control, everything works perfectly.
However, when I stream the content to the Pi via another logged-in user session, Dolphin picks up the pedal inputs, but that's it.  Using Windows game controllers app, I can see all the Axis and buttons as they're being pressed, but somehow Dolphin doesn't pick them up.  If I then log in as that user, the stream cuts out, and once again, I see inputs.

I know it's not an issue with VirtualHere, because other applications like Retroarch, RPSC3, Supermodel all work fine.  I can't work out why Dolphin in particular only picks up two axis while streaming/while that user session isn't active.  Input is completely turned off in Sunshine.