Fixed on your site and the next release. This occurs when two uneditable sections are in a row, or when an uneditable section occurs inside a section that is otherwise editable. Uneditable sections were not wrapped in separate containers since the extra HTML was not needed to designate the blocks for quick-editing.
This is fixed by giving uneditable sections their own containers, while maintaining the editable hierarchy. To accommodate the first occurrence, additional CSS is needed, which will require template updates during an upgrade.