No overlay, loads video below footer

I have been working on a new install using Royal Pretty Photo to display videos in an overlay. I have used the same combination of plugins and theme components, but today I noticed that this install does not behave correctly, and I have one other recently updated site that is also now broken after the updates. I am using the DIVI theme.

this site has both divi and royal pretty photo and it has not been updated recently. it still works. click the “watch trailer” link: https://america1979.com/

this site also still works correctly: https://offlinersmovie.com/

but this site has been recently updated and it does not work, when you click the watch trailer link you will see what I mean, it loads below the footer.
https://saturnsavedme.com/

I am working on a new site, and have barely gotten started, and have this same problem, where the video is loading below the footer…

Anyone else having the same issue? How to fix?

https://www.ads-software.com/plugins/rt-prettyphoto/