After completing a website, I noticed some white blocks appearing when scrolling. You can view the site here. This issue occurs on both mobile and desktop devices during the initial load only. Could this indicate that the page has not fully loaded yet? If so, perhaps extending the loading screen time could solve the problem. How can I determine when the page is completely loaded? If it's not due to loading issues, what else could be causing this glitch?
To replicate the issue, open the website in a browser, wait for the loading screen to disappear, then use the mouse scrollbar to scroll down (the issue doesn't occur with the on-screen scrollbar).
If you access the site from a mobile browser and scroll down, you'll notice the white blocks more clearly.
I'm unsure why you're unable to reproduce the problem. Please refer to the screenshot I've attached from my mobile device. The white blocks appear while scrolling up and down. See image: https://i.sstatic.net/NfbtJ.jpg