vorticey,
That blade has an aluminum spar, and is shown in high speed level flight. I doubt that the track looked too bad, as the movement at the tip would not be apparent to the crew. Each blade would pass through about the same space, so the tip path would look reasonably sharp, it just would not be flat, but we usually don't measure that do we?
This is my guess, perhaps some ppruner could translate the German narration, which might shed some light (although it might have been made by someone who was misinformed, ofcourse).
I know of no more recent such footage, although the weight and size of tv cameras should make this kind of video very easy to get. Certainly the size of the deflections we must induce in our fatigue tests of blades make me think these motions are fairly normal, even on today's blades.