Problem with responsive background video

I have a fullscreen video on a background, but when viewed on a tablet or smartphone there is a small frame that loads the viedo in 16:9 format over the same video… It doesn’t happen on desktop. I don’t know how to fix it. Thanks for any help.

Here the link to a screenshot: Imgur: The magic of the Internet

Here is my site Read-Only: Webflow - Noran AG - Final

Webflow site link: