That's so weird that the video won't load. It is fully uploaded to Youtube and the link is correct... but then, quite a few people, even experts, have had trouble getting images and videos onto Apple discussions lately... I will try one more time, pasting it into the body of the text instead.
https://youtu.be/o7uTyzz0nbo
Re OS versions, I've been using TextEdit colour pickers since about 1998 (if I remember right) or at least since the beginning of the 2000's. Never had trouble with it before on any version of OSX to the present day.... And it was fine on Sierra until that glitch. I'm dreading having to reinstall my OS, but it may come to that, since Quicktime and Preview have started misbehaving too.
🙂