How to fix jolting/teleporting anchor points as screen aproaches distination

I’m making the follwing website for a client:

When you click a menu item it drags the screen to an anchor, which is great. But Instead of sliding smoothly into place like my anchor menus did in Editor X seemlessly, see how it has this jolt effect as it gets close to destination. You can go to the website to see these jolts. After using the website for a few minutes, the jolts sometimes go away. What’s your experience when you use the website on your screens? Now, my Anchor points are invisble lines placed -80pixels above the section, this is so the sticky menu doesnt cover any content. This could be casuing the problems. But again, this was never a problem on Editor X and I’ve always done it this way because I like using sticky headers instead of fixed headers or transitioning header.

Question:
Can someone help explain how I can fix the jolts upon first entering the website and using the anchor menu?

Question:
Usefull feature idea, you can label any section as a anchor, or an item as an anchor as well. It would be usefull for underneath the tick box to ‘add an anchor’ if there was an additional setting to add an offset in pixels, to account for a sticky header, example offset of 80pixels, for a 80 pixel header.
Thoughts on this addition, would it be usefull for anyone else?