Phantom grey box that only shows up when I view on my phone

I implemented a toggle that shows different parts of my new blog on mobile.

Unfortunately, a phantom grey box shows up when I view it on my phone using chrome and safari, but doesn’t show up on the webflow preview or on the desktop code inspect.

How can I get rid of it?

Here is a screenshot from my phone’s browser. The strange box shows up when your scroll down. The toggle has to be flipped too :

Here is my site Read-Only:

I also have it live, which might be easier to view on mobile: