Javascript Error on Fullscreen Slider

Hi Kriesi Team!

We recognized some jquery Errors in the Console on using the Fullscreen-Slider-Element on a page. This errors only appear on using the slider elements.

Uncaught TypeError: can't access property "userAgent", s is undefined
    [25]< https://www.nrgkick.com/wp-includes/js/mediaelement/mediaelement-and-player.min.js?ver=4.2.16:12
    d https://www.nrgkick.com/wp-includes/js/mediaelement/mediaelement-and-player.min.js?ver=4.2.16:12
    d https://www.nrgkick.com/wp-includes/js/mediaelement/mediaelement-and-player.min.js?ver=4.2.16:12
    [6]< https://www.nrgkick.com/wp-includes/js/mediaelement/mediaelement-and-player.min.js?ver=4.2.16:12
    d https://www.nrgkick.com/wp-includes/js/mediaelement/mediaelement-and-player.min.js?ver=4.2.16:12
    r https://www.nrgkick.com/wp-includes/js/mediaelement/mediaelement-and-player.min.js?ver=4.2.16:12
    <anonymous> https://www.nrgkick.com/wp-includes/js/mediaelement/mediaelement-and-player.min.js?ver=4.2.16:12
mediaelement-and-player.min.js:12:141043

Uncaught ReferenceError: mejs is not defined
    <anonymous> https://www.nrgkick.com/wp-includes/js/mediaelement/mediaelement-migrate.min.js?ver=029dd7591f1357e38b0213dd6faaf88f:1
    <anonymous> https://www.nrgkick.com/wp-includes/js/mediaelement/mediaelement-migrate.min.js?ver=029dd7591f1357e38b0213dd6faaf88f:1
mediaelement-migrate.min.js:1:14

Uncaught TypeError: n(...).not(...).filter(...).mediaelementplayer is not a function
    initialize https://www.nrgkick.com/wp-includes/js/mediaelement/wp-mediaelement.min.js?ver=029dd7591f1357e38b0213dd6faaf88f:1
    jQuery 2
wp-mediaelement.min.js:1:834

We already deactivated most of the other plugins without success on getting rid of the errors. Any clue what to do?