'No Category' filter not working

Hi, I have three widgets displaying ‘natters’ (a custom post type) on our homepage.

• One displaying 6 from the ‘Late Availability’ category.
• One displaying 6 from the ‘Special Offers’ category
• And one displaying 6 that don’t have any category.

However, this last, ‘No Natter Category’, filter doesn’t filter any and instead outputs the latest 6, no matter what category they have assigned.

Here’s a screenshot clip of the filter in question.

Is this a bug?

Many thanks, Matt

https://www.ads-software.com/plugins/flexible-posts-widget/