[Milhouse]

4.14.12 kernel issue resulting from the Meltdown changes 

Isn't KPTI supposed to be disabled for RPi?

Yes, however the KPTI changes which are present throughout the kernel may be producing unexpected/unintended results even when "disabled".

Edit: This is worth a read: http://kroah.com/log/blog/2018/01/06/meltdown-status/

I honestly don't know if the KPTI changes will cause issues on ARM, but given the nature of the issue and the solution, maybe it's possible. Of course, the video issues might be something completely unrelated - I've no idea at this stage as it seems very hard to reproduce (for me, anyway). There didn't seem to be any obvious Kodi changes in #0108, so the most likely candidates are either firmware or kernel.