After messing around with different settings, I found that the two short codes worked simultaneously when I deselected the Blog Page designation under Settings>Reading. Something in the CSS specific to the blog page conflicted maybe? It is definitely odd. As long as things now work, I’ll move ahead rather than try to troubleshoot. I’m just letting you know for future reference how I worked around the issue.
It seems like you’ve created a static page, placed 2 WPSP list shortcodes and then assign it as the Posts page on Settings>Reading?
If that’s the case then it makes sense why the shortcodes were not working.
Assigning a page as the Posts page on Settings>Reading turns a page into a default blog index page. This means, it will disregard all the contents of the page (including the shortcode) and place a Blog list in it.
I’m just letting you know for future reference how I worked around the issue.