Issue with displaying sections with relative position (URGENT)

Hello community,

I urgently need help. I just finished a website, where the 1st section is sticky and the other ones go at the top of it. I used sticky for the 1st section, and for the rest, I used relative position. But I noticed after publishing the website that while navigating inside safari or chrome some of the sections with relative positions appear to have no bg color, or not appear at all, so you can actually see the first section while scrolling… This is particularly happening on mobile.

Why is that happening? Does someone have had any experience with this issue?

Live link: