Right, I can reproduce this every time now and it definitely seems confined to safari.I have problems with the scrolling response of the trackpad being very sluggish. My fingers can move all the way off of the trackpad before the screen even starts moving.
Strangely, this happens on my M4 MacBook Pro, whether using the built-in trackpad, or the Apple Magic Trackpad in both wired and wireless modes.
But it's fine on my M1 MacBook Pro. No sluggishness there at all.
Strange.
It's very subtle but it's possible with the trackpad to scroll a window a few pixels leftwards when scrolling if you aren't dragging directly down. In safari it'll stop scrolling if the window contents move. Chrome isn't affected bytes, you can see the contents shift slightly leftwards but you can still scroll.