TLDW: MegaLag found code and rules in the Honey extension that modifies behaviour specifically to make discovery of non-compliance with affiliate programs and affiliate poaching harder for testers. This behaviour has been in place since 2017 at least.
It’s legit offputting, but when you’re on YouTube it makes sense to play that game. Following a thumbnail meta will get your video more engagement, they even allow A/B testing of thumbnails to find the best performing one. YT is as much a thumbnail platform as it is a video one, and I’m only being slightly hyperbolic.
Yeah I kind of roll my eyes at it, but I get it. People have to earn a living and feed themselves, and they can’t do that without clicks.
And really, pulling a dumb face on a thumbnail is a hell of a lot more ethical in terms of driving engagement than some headlines you see that are so misleading they may as well be outright lies.
There are also various browser extensions to show you an image from the middle of the video instead of a thumbnail. I personally prefer that.