I have de-activated all other plugins on the site and tested with the Twenty Twelve theme instead of my theme and am still having the same problem.
The other plugins I'm using on the site are:
Contact Form 7
Debug Bar Actions and Filters Addon
Featured Link Image
Force Regenerate Thumbnails
Google Sitemap Generator
Post Tags and Categories for Pages
Wp User Frontend Pro
Please let me know if you need more information of if I'm doing something very wrong. 🙂
First you've to setup the post editing page, take a look. It's needed for post editing.
The problem you are facing is happening for “Override the post edit link” option in the settings area. It overrides the post edit links in order to easy post edit navigation in the frontend. You might turn it off if you want to.