Incredibly critical issue with Ad blockers killing h5p iframe content, even the h5p.org example for Column
I've seen responses about not being able to reporduce. Trust me, it's absolutely happening.
https://h5p.org/column#example=54549
With ublock origin enabled, there is no column on that page.
Basically, all development needs to go to fixing this since adblockers are so common. This is an unmitigated disaster for h5p if large swathes of users just think pages are broken.
Edit: This list in question is EasyList