WP_QUERY orderby not working with posts

I’m trying to make a simple Wp_Query() where I get 3 latests posts on my blog.

Easy:

// WP_Query arguments
	$args = array(
		'post_type' => 'post',
		'posts_per_page' => 3,
		'orderby' => 'publish_date',
 		'order' => 'DESC',
 		'post_status' => 'publish',
	);

	// The Query
	$post_query = new WP_Query($args);
	
	if ( $post_query->have_posts() ) { and here goes the loop }

But it’s not working for me:

I’ve already tried sorting with:

	$args = array(
		'post_type' => 'page',
 		'order' => 'rand',
	);

and also by date, by ID, and the query works perfect. But when I try to order ‘post’ type, it won’t work.

I’ve also tried to show the query (var_dump) and it’s also working as intended. But when it comes to load the page post order won’t change no matter what.

To sum up, I can get pages ordered whichever way I want but I cannot do it with posts using the same code.

¿Any idea of what else can I try?

Thx