Sorry for the delay in replying guys. Been up to my eyeballs in crap these days :)
 
So it appears this is indeed a bug. Just for grins and giggles, I switched the Ultralite to a different USB port and the problem went away.
Unfortunately it came back again and the only DAW related activity was opening Studio One and playing around with Reaper a bit.
After closing everything, doing a clean boot, the problem was still there until for some odd reason it disappeared again.
When it was failing, I did try playing around with the MOTU Discovery app, changing AVB settings, sample rates etc to see if I could fix it but no luck there.
 
I'm going to disable it in Windows because my fear is that something may be in a feedback loop sending high frequencies above my hearing range "somewhere", like my monitors, and ultimately toasting my tweeters or something else.
I agree this 1-24 thing in Windows is confusing and I'm not sure what programs would even use it?
Maybe some 5:1 systems?
I dunno.
I'll file a bug report with Motu as soon as I get a chance.
It would be good if others could do the same. 
Hopefully it gets fixed in the next driver.