If you have Chrome on mac, can you try this for me?
https://donations.speakernet.co.uk/
Go to this simple payment page, and scroll UP with a mouse wheel. On Firefox, the header stays pinned to the top and the content slides underneath. On chrome, once you reach the bottom of the scroll, the page starts to slip off the top.
The same on scrolling down, once you reach the end, the header starts to get dragged down and is no longer fixed to the top of the screen.
I'm trying to establish if this is my machine or more generally an issue.
The page is designed with Tailwind and has fixed applied to the header which gives it position absolute.