Ok did some more research on this. From your site in the footer I saw you were using the Simply Red theme from ThemeLab. It’s free so I downloaded it and applied it to a local WP 3.0 site I’m working on. This site is NOT running the Simply Exclude plugin by the way.
I setup the sidebar widgets to include Categories, Tag Cloud and Archive. Just like your site I disabled permalinks. This will provide the nice URL like your example Resources page /?cat=5
I setup a Post. I added a sentence to the post body. I then added some images from my drive and inserted the default gallery shortcode ‘[gallery] below the simple sentence. I then added the Post to a dummy category. When I view the front end of the site the dummy category is listed in the sidebar.
When I click on the sidebar category link it take me to the category archive page. Normally this will be a listing of Posts in that category. In my case this just shows the one dummy post I’ve entered. You know what the gallery was not displayed. But if I click on the title of the post I’m taken to the single view page. Here the gallery does display.
My thoughts:
When viewing an archive (or even the home page) more themes call the WP theme function ‘the_excerpt()’. At one time this function called the PHP function strip_tags which removed all HTML from the content. I thought this was corrected to allow certain HTML codes.
Back to your site:
If we go back to your Resources page https://blog.whenlovefalls.com/?cat=5 again your shortcode (I’m assuming it is there does not display. Also you noted the download link is not there ot is not a link anymore. This is typical of the PHP strip_tags() function the link/anchor text remains. At this point if you click on the title of the one post listed you will be taken to this page https://blog.whenlovefalls.com/?p=21 Here the image is displayed and the download link is working.
So I guess the open issue is why is the WP function the_excerpt removing the shortcode the link html? Again, this was reproduced on a new WP 3.0 install and not running the expected culprit Simply Exclude plugin.