CustomPress prompt when clicking publish

Hi guys,

Why is it that every time I click "publish" on a post, a box pops up asking me if I want to leave the page?

This only happens on my custom post type.

wp-post-new-reload=true is immediately added to the url when I click publish.

The only error in my console is:

Failed to load resource: jquery.ui.datepicker-WP.js

I'm using the latest version of WP and CustomPress.

Any help would be appreciated.

Regards