Hi,
on certain websites when I scroll with mousewheel it often stops for 3 seconds.
I usually wait, and scrolling this page is then OK.
Sometimes it happens at the half of the page, other times at two thirds, or even at the first third.
There is no problem ever when I click and drag the scroll bar.
I typed opera://flags and tried to tick/untick various options.
My problem seems gone by disabling Threaded scrolling.
Just my 2 eurocents...

Thank you for your work & Have a nice day