Slider Background flashes through when scrolling down with mouse

[jimano]

Hi there….I’m kind of e newbie and setting up my first WP site…I hope I can get some help here because I was unable to find it searching with Google.
I made a WP Homepage using Elementor. I used a slider for my header and set this widget as fixed position so that the rest of the content will scroll over the slider. When I take a look at the website and scroll down with the mouse button the slider background flashes through especially on the places where 2 Elementor widgets are joined. It gives the website a very unprofessional look.
What can I do to prevent this…any suggestions? This might sound like a newbie question as I said before I am quite a newbie Thanks for your time and help in advance!