Tested in Moodle 3.11,

Course format:  format_tiles 3.11.1.3 (2020080629)

Browsers: Chrome and Firefox

1. Create a new course with Course format tiles
2. Embed a big amount of audio or video URL in an acitivity label
3. Turn editing off
4. Switch between the tiles/sections or reload the site of a section in the browser
5. A Javascript Error displayed in most cases:

The element or ID supplied is not valid. (videojs)
File: https://.../lib/requirejs.php/1643046412/media_videojs/video-lazy.js
Line: 1
Stack trace:

ln: 226339
https://.../lib/requirejs.php/164
Ze
ln: 3939
https://.../lib/requirejs.php/164
t/</<