"Delete" image only partially works

I have a post image field added to my form set to be the featured image of the post. When trying to “edit” the post from the front-end I can see the uploaded image and a “delete” link. However, the “delete” link, when clicked, does visibly nothing. Upon save, however, the image has been removed. I’d expect & assume the “delete” link should be replaced with an image uploader field when clicked, however, in my set up this is not the case.

WP 3.8.1
GF 1.8.9
GF:PU 1.2.13

Thanks for your help!

https://wordpress.org/plugins/gravity-forms-post-updates/