Just to clarify, the issue of the contrast color desaturated when exit the video is present on my iPad 4, for a few seconds.
But the problem of the continue flickering during the video, which is a real issue, seem to be non existent on my unit
A week and half old iPad 4 here and no "pumping" issue at all.
The only thing I managed to kind of replicate is the issue with the icons just like you but I have to try a few times before it happens. The colors could revert back to normal a little faster I suppose, but other than that I don't think it's far from a regular behavior.