Waoo, thanks for that observation, I just noticed that now. You are right.
First of all, the minimal demo was actually created from this starter template https://stackblitz.com/edit/react-6rzfpp?file=src%2FApp.js
Let's focus on the Layers page.
The issue is that, the sections in the layers page must be 100vh. What we have content that are more than 100vh, and i still want to maintaining the layers animation.
Once we scroll down to the end of each layers, it looks like it's pin while the other section overlay it. But this time, the height is not mandatory 100vh