Wierd Result Using "Listing" Widget

I add a “Listing” widget on the right sidebar and made the following query to list only featured listing randomly:
meta_key=featured&meta_value=yes&orderby=rand&post_type=listing_type&posts_per_page=6

The weird part is, the list changes randomly when any of the navigation menu is selected, but… the list remains the same order (unchanged) when selecting ads.

See screenshot:
1. Settings I made
2. Two different result

Please check it for yourself at http://www.mixph.com