Shortcode at excerpt

Hi, I need to show a small shortcode plugin that I´ve developed that calculates time-remaining to an event. But it is not showing at excerpt, but ok at the post. Is there any filter removing it? Is so, what can I change to solve this issue? (i´m using child theme to do this). Initial text...[regressiva data="dd/mm/yyyy hh:mm"] more text, bla bla bla, readmore tag, more tag, etc...