multiple custom post types problem

also, the problem arises when i check the “has_archive” option for the new custom post type

Are you seeing both (or wrong) post types on frontend?
like when visiting URL: https://mysite.com/events/

Can you check rewrite slug settings?

Hello,
I actually solved the problem. It was caused by using this function:

function namespace_add_custom_types( $query ) {
  if( is_category() || is_archive() || is_tag() && empty( $query->query_vars['suppress_filters'] ) ) {
		$query->set( 'post_type', array('post', 'prodotti', 'eventi', 'slideshow', 'nav_menu_item'));
	  return $query;
	}
}

Enclosing the IF function in if(!is_admin()) { } solved my problem.

Thanks for your feedback.