When the zoom scale is small, the scrolling by finger touch is not smooth, resulting in the page shaking up and down. This issue becomes worse as you zoom out smaller, being moderate in bigger zoom scales.
The problem seems to become easily noticeable under around 100%, but there is no clear "threshold" zoom value, since there is still a little shaking in around 180% though it is not much of nuisance.
This doesn't happen in other finger scrolling occurrences like on Edge, so I guess it is the problem with your app, not a hardware or Windows problem.
I hope you will find a fix for this soon.
Thank you for making and improving this great app