Thanks for posting the video. It illustrates the glare problem with Vortex Viper scopes pretty well. There seems to be a lot of glare in the last video of the tree, even at medium magnification and with a long sun shade. As the magnification approaches 24X the contrast really degrades.
That's consistent with my own experience with Vortex Vipers. I have not seen that kind of glare in a comparable Nightforce, to which you compare the Viper. I think higher contrast is one of the things you get for the extra $400.
After reading Bruce's comment I took me Vortex 6-24x50mm PST FFP MOA SCOPE out on my deck. Using my bipod I was able to focus on different objects and different light intensities at different powers from 6x all the way up to 24x. I tried to see if it looked like in the video, but it looked much clearer and brighter then the video.
If the Vortex scope do have something like Bruce says it must be so slight that I can not see it.
PS: Maybe the sun shade was getting a reflection because of the position of the sun ???