Hi @chet,
I am not sure how they set the Vimeo but I tested the case with the version 2.2.5 of the Essential Grid and I still get a black background in the grid with no video available.
If you change the theme to the default theme of the WordPress you will see the same case, so that shows it is not related to our theme and there is no conflict.
We already added this to the issue tracker. You will need to wait for the upcoming release of the Essential Grid and at the moment we can not help you out as this is something related to the Essential Grid itself.
Our dev guys will surely be in contact with the developers of the Essential Grid but you will not get an update here. You need to wait for the upcoming release and follow up the case checking the changelog:
https://theme.co/changelog/
Thank you.