Likes from logged in views do count, the like to view ratio is higher due to that.
A German YouTuber tested it with an unlisted video, I can’t find it as of now but I do find a lot of deleted videos in my liked ones…
Basic theory as of the time of the video is that they want to go against bot views. Short views did not decline, only long form video, and of those the people with mostly desktop views are hit the most.
Edit: found it!
How exactly? Because if it was just watching the video and looking at the view count shown under the video as others making this claim have done: That thing isnt updated in real time and also fuzzes the real number making this way of testing misleading.
I am not sure about the AdSense metrics page, tho.
I’ve heard before that you need to wait 24h before checking the view count again. Although, yeah, I believe you can get more up-to-date counts as the uploader.