The following may interest:
‘Cannot scroll on Downdetector with shields on - #11 by 289wk’
I used the Brave Browser > Developer Tools > Network window, in order to chase down a Downdetector.com webpage display bug, where the browser window’s right-hand, vertical scroll bar is being forced to disappear.
Maybe you can observe something in the Developer Tools > Network window, that helps you. Possibly some thing - when blocked - changes the stutter situation.
Maybe compare the Developer Tools > Network window activity, Brave Browser Stable vs Brave Beta.