Bugs in content types

When I try to embed an interactive video in a label  (embed code generated by h5p) in Moodle 3.3 the only result I see is a black bar with the text: 'Video player loading...' (see attachment). When I drag the browser window to my other screen, it suddenly works.

It's a riddle to me. Does anyone has a suggestion for a solution? Would be great!

Hi friends,

so as I see there is a bug in Image Juxtaposition content type only for new Mozilla Firefox 59.0 (64 bit).
Slide function of images sometimes does not work or work quite hardly.

In browser console appeared those alerts:
1. Error: Syntax error, unrecognized expression: #
2. Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user’s experience. For more help http://xhr.spec.whatwg.org/

When I "Export text," the Microsoft Word file shows extra HTML markup.