Bugs in content types

I have created a reasonably complex branching scenario with scoring within my Wordpress site (version 5.3). It was displaying and previewing for the first few levels of branching but now that I have built the whole scenario it won't preview and I can't get it to display from the H5P Content list.

The error message I get in Explorer (version 11.476.18362.0) is 'mywebsite.com is not responding due to a long running script'.

1. Using Image Hotspot content type and attempting to add a .vtt caption file and to the Track file (WebVTT) of a video. After adding the WebVTT file, it errors out - "File type isn't allowed". Will not accept ANY caption files.
2. Drupal
3. Desktop
4. Chrome, Firefox
5. Image Hotspots (1.8.2)

Hi; 

Is it possible to merge the inline Js& CSS from H5P with other files?

or how to load statics JS/CSS assets during the page load instead of loading them on front via a JS.

FYI, I am using "WP rocket" with WordPress in order to increase the speed of the site.

Best regards.