Hi Neil,
Based on what Iam seeing regarding the "flashing" tree, I would not change anything just yet.
I think it is a function of this Beta. So far I have only seen it while in Driver, not in Surveyor 1.0.
I have yet to make a real stab at trying S2.0....Grin!!
(you know, Old Dog....New Tricks)
Do you have shader on "Ultra?" If so set it on Standard and see if the tree flashes. I have quite a bit of "flashing" on some routes if on "Ultra." Or is this something other than that? I'll run the route some more today. I ran it about a week ago on "standard" shader and didn't notice anything but I could have had my head turned at that moment.....