Wrong subdomain in Permalinks

I have this very strange problem with my site and I can’t find any way to fix it.

My site should point to a URL: http://www.site.com
My WP_HOME and WP_SITEURL in wp-config.php and the wp_options inside my database are both indicating the correct URL.

Now the strange thing. If I go into the WP setting in any of the following locations:

Settings -> Permalinks
Posts -> Add new -> Snippet Preview (under the post editor)

The link is indicated as: dev.site.com (instead of www). So all new posts and new links are poiting to dev and not www.

I can’t find any place in the settings to change dev to www. Does anyone have an idea how to do this?