Hi Spyros,
Do you mean you have placed this code in your excerpt section ? By default excerpt doesn’t run shortcode. And the code your mention above as shortcodes created by you slider. So if you want to use them then you need to place this code in your functions.php
add_filter('the_excerpt', 'do_shortcode');
For details, you can check this thread from wordpress.org. https://wordpress.org/support/topic/shortcodes-dont-work-in-excerpts
Thanks