Hi there,
I’d been experiencing an issue with shortcodes in the beta and just confirmed it’s still there in Beta 7. When adding any shortcode to a page, the preview still works. However, after refreshing the editor or going back later, the preview is not showing. In my case, I’ve added several types of shortcodes (Mailpoet forms, Gravity Forms, Toolset views, Toolset forms) to content areas and the issue occurs for all these shortcodes.
As soon as I remove the shortcode from the content area through the page outline, the preview appears and works fine. In some cases, as soon as I put the shortcode back any edits in the page are then no longer eflected in the preview.