I'm intending to look into this myself, but figured opening a ticket would give more visibility.

When running a test with mobile emulation, the LH report shows that the Chrome-Lighthouse UA modifier is present (as expected). However the LH report for a test with no device emulation does not have the Chrome-Lighthouse modifier.

I'm pretty sure the only difference between the LH commands for these tests is the desktop run has the --emulated-form-factor=none flag set. I wonder whether it should actually be --emulated-form-factor=desktop?