Problem in scrolling Youtube page on Safari macOS Big Sur

I find this occurs when the 'vertical elipsis' (three vertical dots) appears to show more comments are available.

If you scroll on the very left of the screen (to the left of the avatars) it seems to work smoothly.

Just an update - for me at least, the issue has apparently been a bug in a third party app called Mos for smooth scrolling. disabling that sorts out the bug for me.

Mos user here as well. Disabling Mos will correct this issue for the trackpad. Thanks!

@AargauSteve

Thank you for your solution.

I have exactly the same problem on Safari 14.0.1 on Mojave 10.14.6. My workaround was to use arrow keys but it's pain the rear end. Positioning cursor at the left edge of youtube window to the left of the avatars works around the bug really well. But I found the scrolling bug persists no matter if vertical ellipses is in view or not. As long as you are anywhere but at the left edge you can't scroll with two fingers. Hope this helps to clarify the workaround, and hope Apple fix this bug soon.

Once you install the extension (Usersscripts from the app store) Go here: https://forums.macrumors.com/threads/youtube-website-scrolling-issue.2272026/?post=29355750#post-29355750

All the code is there to copy and paste.

Then literally copy line by line exactly what you see in the screenshots (above and on the webpage, they have actually screen shots of the app), press "save" and then refresh Youtube. Works perfectly :)

Apparently there’s some issues with web styling in YouTube, so this lovely person has created a temporary workaround, see image for instructions. Once you’ve installed userscripts Safari extension from the App Store, enter the CSS code in the extension and save the code. Now refresh youtube and it should work perfectly.

Credit and a big thank you to Gnattu over at MacRumours forum for the fix!

I had the same problem before. I starts after updating Safari to version 14.0.1 and higher on Big Sur and Catalina as well. I am on Catalina now and did a rollback to version 14.0 for Safari. This is my way to solve that.

I have this issue as well. I have a MBA M1. The only thing that has worked for me was a restart. The issue will go away for a couple of days, but return...

I try to use Brave instead since it's Chromimum and lighter.

On YT's main page, scrolling is working fine for me, but in any video, scrolling seems 'sticky', like starting scrolling (in any direction) the page seems 'stuck' until enough 'scroll action' is input, then it becomes unstuck and glides. Once it stops, though, the same issue occurs.

It seems to be 'inertia'-based. Turning off inertia when scrolling breaks scrolling all-together on a video's page.

Once the extension is installed, you click on the extension in the toolbar of Safari, which will load up userscripts extension, then you create a new userscript and enter the text as per the screenshot I’ve added above previously. Hope this helps

I believe the scrolling/web styling issue with Youtube is specific to Safari 14 (which is available for macOS 10.14-11.0. Not sure if it affects earlier versions of Safari, but I didn't notice it when I was using Safari 13. I think a fix will most probably have to be from Youtube, as the scrolling issue doesn't seem to affect other websites?

I'm also experiencing this on an M1 MacBook Air running Big Sur 11.0.1. My first thought was that this was intentional, because it's hard to believe they wouldn't have done testing on one of the most popular websites in the world. But it does seem to be a bug.

This is the most annoying bug I've encountered in recent memory. Apple has to be aware of this, or providing a fix soon. Until then I guess I'll just keep moving the cursor to the left side of the page on YouTube in order to scroll.

FYI, this is NOT a Big Sur problem. I have the same issue on Mojave 10.14.6 using Safari 14.0.1.