exluding category messing up post order

Hi,

In my functions.php I am using the following code to exclude a category in my entire site for non-logged-in users.

if (!is_user_logged_in()) :
	add_filter( 'pre_get_posts', 'exclude_category' );
	function exclude_category( $query ) {
		if ( is_feed() || is_home() || is_archive() || is_single() || is_search() || is_page() || is_paged() || is_author() || is_tax() || is_tag() || is_category() || is_singular() ) {
			$query ->set( 'cat', '-5' );
		}
	}
endif;

When testing locally (MAMP) this works perfectly but as soon as I uploaded it to my site it totally messed up the post order.

Any clues on what’s happening here? How to avoid this?

Thanks a lot for any help!