Mixed use of PHP and Shortcodes

Thanks a lot for providing such a useful plugin. I am currently evaluating it together with your new Pho theme which I like a lot, especially how it is documented.

What I am trying to achieve is the conditional insert of a shortcode on my front page, so I have inserted this into tha_content_top:

<?php if ( is_front_page() ) {
  echo ("[shortcode]");
} ?>

Both the PHP and shortcode options are checked, but what happens is that the shortcode is printed but not triggered. If I enter the shortcode directly in the tha_content_top field without using PHP, it works fine.

Am I doing something wrong or is this just beyond the scope of this plugin?

Thanks a lot in advance.

https://www.ads-software.com/plugins/tha-hooks-interface/