Wordpress query adding 0=1 in wp_query and result dissappear

Question

Wp query adding 0=1 in the query and results disappear, I am trying to adding multiple taxonomies in the query but it is producing 0=1. I am trying to fetch results from multiple taxonomies and in case of all I am passing a blank array to get all results

$category = array('');
    $post_regions = array('');
    $post_tag = array('');
    $post_categories = array('');
    if($_POST['pageType'] !== "all"){
        $category = array (
                'taxonomy' => 'category',
                'field' => 'slug',
                'operator' => 'IN',
                'terms' => explode(',', $_POST['pageType'])
            );
    }

    if($_POST['regions'] !== "default"){
        $post_regions = array(
                'taxonomy' => 'post_regions',
                'field' => 'slug',
                'operator' => 'IN',
                'terms' => explode(',', $_POST['regions'])
            );
    }
    if($_POST['topics'] !== "All"){
        $post_tag = array(
                'taxonomy' => 'post_tag',
                'field' => 'slug',
                'terms' => explode(',', $_POST['topics']),
                'operator' =>'IN'
            );
    }


    $args = array(
    'post_type' => 'post',
    'orderby' => 'publish_date',
    'posts_per_page' => -1,
    'order' => 'DESC',
    'post_status'   => 'publish',
    'date_query' => array(
        'relation' => 'OR',
        $dates
    ),
    'tax_query' => array(
        'relation' => 'AND', 
            $category,
            $post_regions,
            $post_tag,
            $post_categories,
        ),
);

$query = new WP_Query( $args );

Answer 1

Define the empty array like this:

array();

If you define a array the way you do:

array('');

then array[0] is set.

Regards Tom