Did you try Firefox in Safe Mode?

I don't have that issue. see screenshot https://www.youtube.com/watch?v=gHfe1xTpomE

I have the same issue. After i check the youtube extension. I see there is problem on ublock origin extension, after i disabled it. It running well

Did you try Firefox in Safe Mode? I don't have that issue. see screenshot https://www.youtube.com/watch?v=gHfe1xTpomE

After checking the extension too, i see the problem is on extension ublock origin. After i disable it, it running well

Did you try Firefox in Safe Mode? I don't have that issue. see screenshot https://www.youtube.com/watch?v=gHfe1xTpomE

after checking the extension, i see there is problem on ublock origin extension. After i disabled it, it running well

I have the same issue. After i check the youtube extension. I see there is problem on ublock origin extension, after i disabled it. It running well

You're right, YouTube displays fine after disabling the uBlock Origin extension. But then there are adverts. Do you have another way to get the video to display properly without keeping the adverts? Because the display was normal before I updated to the latest version.

I use Adblock Plus. https://addons.mozilla.org/en-US/firefox/addon/adblock-plus/

I use Adblocker Ultimate for youtube

https://addons.mozilla.org/en-US/firefox/addon/adblocker-ultimate/?utm_source=addons.mozilla.org&utm_medium=referral&utm_content=search

Try updating the uBlock Origin filter lists. If it still happens, try clicking the "Reset to default settings" button.