This is absolutely bonkers. Because the ML stuff used for “Look Up” and “Copy Subject” is taking a while, the menu item positions are changing around (multiple times!) under your mouse cursor. I’m not sure if there’s a simpler and more straight-forward rule in all of UX design than to never do that. I had to stop using Safari because of how often this would make me click the wrong thing.

(To the surpise of absolutely no one: The movie sucked.)