Hello @shughesd,
Thanks for writing in!
When you click the “Edit in Cornerstone” button, there is a JS notice that displays in the console:
Unable to launch Content Builder from Gutenburg TypeError: Cannot read property 'getCurrentPostId' of undefined
at b (dashboard-post-editor.js?ver=3.3.8:1)
at HTMLButtonElement.<anonymous> (dashboard-post-editor.js?ver=3.3.8:1)
at HTMLBodyElement.dispatch (load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-mouse,jquery-ui-sortable,jquery-ui-draggable,jquery-u&load[]=i-slider,jquery-touch-punch,iris,wp-color-picker,quicktags,jquery-ui-position,jquery-ui-menu,wp-a11y,jquery-ui-autocomplete,unde&load[]=rscore,backbone,wp-util,wp-backbone,media-models,moxiejs,plupload,wp-plupload&ver=4.9.8:3)
at HTMLBodyElement.r.handle (load-scripts.php?c=1&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-mouse,jquery-ui-sortable,jquery-ui-draggable,jquery-u&load[]=i-slider,jquery-touch-punch,iris,wp-color-picker,quicktags,jquery-ui-position,jquery-ui-menu,wp-a11y,jquery-ui-autocomplete,unde&load[]=rscore,backbone,wp-util,wp-backbone,media-models,moxiejs,plupload,wp-plupload&ver=4.9.8:3)
Please make sure that everything is up to date. In most case, out dated WordPress, theme or plugins may create conflicts or issues in your site.
Please let us know how it goes.