Forgive the self resuscitation but,
Now I’m back on the vessel . THings have rearrose …
Same issue … now it is only happening with the Display connected , it’s literally as if you unplugged and replugged the monitor (HDMI ) … things go black and then reinitialise … hmmm … this happens at totally random intervals …
Maybe I will try as different compositor …
In my case things have settled after connecting the display directly to the PC instead of a hub. Yesterday some odd colorful flicker occurred but it affected both displays. it’s like we swapped symptoms 
How likely is it that this “weird flicker” was some sort of transferance of energy .
Seems like more than mere coincidence …
To rid myself of sucj ills ,
I will reinstall with GNOME and see . Huzzah!