Please use manual excerpt when using Cornerstone on post. You can do that by editing your post, then go to Screen Options on the very top of your post, then enable Excerpt. Then scroll down until you find excerpt section where you can input texts manually.
Regarding the category page excerpt, it will display excerpt once you have added manual excerpts on those post. Archive pages content like those category page are controlled by a template. That is how it works in wordpress by default. It cannot be edited using any page builder.
For translation, please see this guide: https://theme.co/apex/forum/t/setup-translation/61
Hope this helps.