Transparent video in Repeater?

I’m building a repeater-based design in a section.
The repeater is in List format, with a 5 col/1 row grid.
Whenever I try and add one of the stock Transparent Videos to any of the Repeater grid cells, it won’t attach. (I was going to be swapping them out for my own content once built).

Do repeaters not allow transparent images or video? I’ve tried putting it in its own container first, but no go. I’ve trued using the Layers panel, nada.

Any ideas? Many thanks here is the article with the elements to repeater limitation, @tmgilchrist69214

video box is one of the limited elements