Hi,
1. It might be only due to the multiselection logic. Try changing this option: https://i.imgur.com/ufaHQep.png
In this case results will be displayed whenever at least each of the tags match, it does not have to be both.
2. It does not depend on the post type. Currently I am only seeing 3 post tags on your website, but only 1 has any items associated with them: https://i.imgur.com/FHKfuN8.png
The plugin automatically shows only the tags where is at least 1 post/post type is associated with, because empty tags will not change the search outcome.
If you start adding more tags to posts or other post types, they will start to show up in the list.
