Highlighter tooltip appears despite being disabled

I've had the "Enable Highlighter Tooltip" checkbox disabled because I don't like it appearing every time I select text, and often it interferes with other tooltips.

However, time and again, I see it popping up despite having it disabled. Here's a video of that happening on Medium, but it has happened elsewhere, too:

https://share.cleanshot.com/pLVWZgDb