Interactive Video does not work properly in Drupal 8.9.6

Hi, I am not sure why, but when pupils create new Interactive Videos on my drupal-Site, it happens that their Videos doesn't work in the correct way. There is only a litte part from the first picture on the Video at the top of an article (see screenshot).

This occured a few days and may happens after updating the plugin or Drupal itself to 8.9.6. All old videos worked on the same site without problems!!

- All Videos are fully uploaded on the ftp server (checked Manually)

- When opeing a new broken node with a interactive Video there ist the following failure:

Uncaught TypeError: H5P.DragNDrop is not a constructor

    at new DragNBar (drag-n-bar.js:26)

    at i.attach (h5p-interactive-video.js:1)

    at Object.H5P.newRunnable (h5p.js:954)

    at HTMLDivElement.<anonymous> (h5p.js:137)

    at Function.each (jquery.js:2)

    at init.each (jquery.js:2)

    at Object.H5P.init (h5p.js:93)

    at HTMLDocument.<anonymous> (h5p.js:2821)

    at c (jquery.js:2)

    at Object.fireWith [as resolveWith] (jquery.js:2)

I changed my installation a bit but I can't say if something is causing that problem. I installed some plugins (for example I added plupload, colorbox and Embedded Google Documents Viewer) and other things on the page but if this would cause the problem, I think it could effect older nodes, too. I really hope you can help, because I need this for my lessons.

I just mentioned, that there is a problem in loading the toolbar when adding interactive content to a video. I shows "Lädt..." (which means loading...) without result.

Thank you very much