Hello,
Looks that this is some Revolution slider glitch with the youtube video, we have imported the example from the Revolution slider package https://revolution.themepunch.com/wordpress-youtube-header/ but it does not work on your site even if the default theme is enabled, at the same time Vimeo video works fine https://gyazo.com/e7133fadd93f73d7c5229506b357c8c2
Unfortunately, we can do nothing with this. You need to contact Revolution slider support to find out what is the reason of the problem because we are not plugin developers and don’t have advanced help for the plugin bugs. Or use vimeo/HTML5 video.
Regards