Absolutely NO question, so as Rainwise which is a fine instrument doesn't get any bad rap and because it is the truth, that the effect in the video is a camera effect. CCD cameras and CMOS cameras to a lesser degree, due to the way the image is read, make motion, especially rotating objects, seem goofy.
This illusion is even more amplified with the compression technology that stores the image, and then transmitted to UTube, and when there the 400 hours per second of video they get ingested gets compressed even further, no matter how pristine your video is when it arrives. Sampling time is a factor also.
I've given up on most attempts at showing much on their site, even though much of what I tried was of limited value and not important, it was clear that I had no control over what you think would be seen.
So don't worry, realize it is a faulty not real video, and the complex shape of the propeller is harder to encode than the simple rotating anemometers shown above.
But it is NOT a fault of Rainwise (which one of the respondents hinted at here). I maintain plenty of them and have 6 at home, so other than getting stopped by a build up of heavy wet snow in no wind conditions, they are as reliable as anything out there.