I've just noticed this as I'm prepping a site for launch.
Love this plugin and it has taken over as my fist choice but there seems to be a conflict with Woothemes Canvas (my preferred framework).
For testing - clean WP 3.8 install and vanilla Canvas theme (5.5.7 - latest). No active plugins.
On the surface everything works as it should - the problem occurs when you view an image attachment (ie media library / click view link under image thumbnail).
Rather than just displaying the image embedded in the content area of the page it is attached to the image also displays wherever a Content Block has been used in a widget area resulting in multiple images rendering and breaking the layout.
That is - if I have used a Content Block in the primary sidebar the image renders there as well as in the content area as it should.
Examining the html rendered in the widget shoes that a Paragraph with the class "attachment" has been added immediately below the opening custom_post_widget div tag.
Any ideas? Many Thanks.