I have seen similar problems right after using GMail or watching YouTube videos. Firefox would keep CPU busy even if I closed those tabs. I stopped watching YouTube on Firefox because of this.
This is on macOS.
This is on macOS.
There's a common element here and I'm trying to put my finger on it. It rhymes with Scroogle.
Why is it that the only websites I have issues with (Firefox user) are Google properties?
Google properties have a history of having suboptimal code served to Firefox.
Or maybe, unlike the rest of the sites, Google engineers don't bother to test stuff on Firefox?