Please be aware that most users using ad blockers cannot see a lot of your H5P content as of maybe yesterday.
It appears that h5p content that uses Column is now being blocked since it works with iframes. Check your content.
Edit: This list in question is EasyList
##iframe[src="about:blank"] found in:
Edit 2 Fix: Find the iframe code in your installation and change src="about:blank" to src=""
In Drupal, this is in h5p.module on line 686.
h5p.org needs to do this as well since your Column example is broken with ad blockers.