[robo989]

and the TBS6985 literally disappeared to the system, doesn't show with any modprobe command and not showing up in tvheadend under adapters, it's as if the driver just vanished (!?).

Just installing everything again from scratch and will provide a log with debugging enabled once done.

Do you see the TV Card in the BIOS? There were often BIOS Bugs with PCIe TV Cards in Series 7 and 8 Intel Boards,
maybe they are now in the Series 9 Boards also

I checked the bios and it is indeed there.
I didn't investigate further, re-installed OS/xbmc and everthing working again including previous unrelated problem mentioned on previous page.
Set the PCI-E link to 1st gen from auto, never know may have had some effect, I know TBS cards don't like running on gen2/3 at times.

/Sorry for OT, original problem I assumed was related to the intel onboard gpu.
/As an aside, the de-interlacing set to "de-interlace" is notably better than my old GT430 deinterlacing.