Custom excerpt filter does not cut the excerpt

Hey

I’m trying to shorten the excerpt but it does not work. It shows the full excerpt which I write in the post edit!

I’ve added this to the functions.php

function custom_excerpt_length( $length ) {
	return 20;
}
add_filter( 'excerpt_length', 'custom_excerpt_length', 999 );

Even if I delete the above code it does not show default 55 words. I reviewed all my files and I can’t find the problem.

To show the excerpt I’m using the_excerpt()

Where can be the problem? Any ideas what can cause this?