The reason I say intermittently is because there's a workaround for when the mouse scroll stops scrolling in Firefox and it's... kinda weird. You first need to switch to another app where mouse scroll still works (or launch one), in my case I use Telegram for that as this is what my family uses to communicate with each other, scroll there for a bit, then alt-tab back to Firefox and the mouse scroll suddenly works. And yes, you have to scroll in the other app, otherwise when you alt-tab back to Firefox (using the newest 145 here), the scroll still won't work otherwise. Pretty weird.