i noticed this today

What the fuck

They've done similar shenanigans to cripple Firefox's UX countless times in the past. Never had the balls to target Safari, as far as I know.

Pure evil

I have noticed this for a while now. Also when a clip is running and you click on another one or just try to click away, it keeps running for a few seconds.

WTF!?

Should remove the UTM in your link.

Further down in the thread, it is determined that this runs on all browsers, and appears to have to do with detecting ad blockers, but nothing specific to Firefox.

Just in case anyone is interested.

further down. https://www.reddit.com/r/firefox/comments/17ywbjj/comment/ka08uqj/?utm_source=share&utm_medium=mweb3x&utm_name=mweb3xcss&utm_term=1&utm_content=share_button

Reading the rest of the comments, as others have mentioned, this is not FF specific. However whenever there is an opportunity to discuss Googles growing stranglehold on the internet Ill try to be there.