Thanks for updating the tread.
I tested the Home grid and added into one of the pages using Cornerstone element. I checked the source of the Grid and then inspected the source code of those post and can see that they are created using Cornerstone builder. Upon adding the Essential Grid element I can see the excerpt in front end. I am sharing the screenshot, please take a look.
As you are facing the issue, can you please let us know how we can replicate the problem on our end? Perhaps soe screenshots or screencasts.