Hello and a big thanks in the beginning,
@Richard No, unfortunately I didn't really solve this, yet. You have to check it on mobile phone (not desktop). The browser blocks the video on mobile and the picture is shown. With the bug in the footer area. Can you see it on mobile? It appears now for a short amount of time by scrolling down.
Thank you very much @felix_rabe, it's better now but still the wrong picture / error blinks up for a short amount of time when scrolling down.
Any ideas how to fix this perfectly? :)
Thank you in advance,
Sunnyi