The video explains it best, but for some reason Vimeo widgets are intermittently not loading properly without any rhyme or reason. Hitting refresh will often fix the problem, but the lightbox widget sometimes just greys out the screen and doesn't load the video. Often happens after the site switches breakpoints, but it has both worked and malfunctioned at each breakpoint.
I have only two breakpoints so far, so this site will not work on mobile. Here is a link to the test site: http://testsite.clovehitchproductions.com/work.html
If anyone is able to reproduce this issue, or even better, provide a solution, I would be grateful.
Thanks for providing the link! It looks like their suggestion of using the Composition Lightbox won't improve my results, since that is already what I'm currently using. I hope I can find an answer, as this bug is literally the only thing that is keeping me from finishing the site.