Now I'm not a network engineer and can't say that the video is or isn't a lagswitch but I do know they are easy to make or buy online. I will say that it's somewhat odd that they can move without an issue and you frozen which makes me think it could actually be a switch.
It's hard to say for sure to say if it's purposeful lagswitching from just that video.
I would report people like this just in case, if everyone does this then Ubisoft will see a majority of reports on their account and hopefully investigate.