Thanks @carmine,
I don’t think this works for me. I’m experiencing the problem with the [field url] shortcode even in pages not created in Cornerstone (although X theme applies to them of course).
That’s why I think the new Cornerstone has some conflict in the shortcode definitions specifically in that area.
Other shortcodes by Custom Content Shortcode works amazingly well in Cornerstone (and the [field url] also did, until the Cornerstoe update.