I recently had a project that required me to use Wordpress shortcode inside a Wordpress excerpt. Anybody who is familiar with Wordpress will tell you that: Wordpress does not allow you to use shortcode in excerpts!
You see, you can use shortcodes for anything called through the_content() function, but the shortcode will be displayed as-is when the same post is called through the_excerpt() function. According to the Wordpress Codex, no code or html tags are executed in the_excerpt() function.
executing shortcode inside the_excerpt() in WordPress
