Anyone else have this issue? I thought maybe it was just my removedty surface pro 3 but it happens on my T530, T460s, and my desktop. I thought maybe it was an extension I had so I uninstalled them all except ublock. Still happening. For now I’ve just switched to librewolf and installed all the extensions I had on Firefox. Works fine and doesn’t keep my CPU at 100% so problem solved I guess, but I’m still curious if anyone else has this issue?
Create a new Firefox profile, set it as default, then restart Firefox and see if the problem still persists.