Update:
I decided to test it on the live server, and what do ya know….it worked, super!

So the issue is somehow in using this on the local server.
Not sure the issue, but glad it’s working.

Update: Wow, I was falling asleep at my computer last night when I wrote this…:)
Let me tell you what I did.
I test everything locally before I send it live, so I cloned my site and put it into my local server.
The shortcode would not work.
Through process of elimination my plugins were all deactivated, and I ended up back at the default WP theme, still did not work.
I installed 3 more sites (locally) just for testing.
The first is in the root
The second is in a subfolder with the site url the same
The third is in a subfolder with the site url as the root.

The shortcode worked for one and two, but not three.
I did another install in a subfolder with the site url as the root, and behold, it worked!

Which is puzzling…. since I don’t know why it worked for test four, but not test three since they were the same.

Back to my original site…. I also deleted the htaccess and regenerated by setting the permalinks again, still did not work.
Now, shortcodes do execute on my site just fine. Not really sure what could be preventing the shortcode from working.
I will point out that if I go to the “General” WP settings and temporarily change my site url from “mysite.com” to “mysite.com/subfolder” then everything works fine.

The addon (frontend) does recognize the parent plugin, so that’s ok.
Any ideas I might test, or what might cause an issue?
Could it be related to permalinks and the “function form_hidden_input()” function?

Any ideas would be appreciated!
Thanks