Problem with santize_callback function

Hi,
I have a text field in a block and set a callback_function in order to format the input data but it is not working.
What am I doing wrong?
This is how I defined the block with the amount text field:

add_filter( 'rwmb_meta_boxes', 'your_prefix_register_meta_boxes' );

function your_prefix_register_meta_boxes( $meta_boxes ) {
    $prefix = '';

    $meta_boxes[] = [
        'title'    => esc_html__( 'Test BLCK', 'text-domain' ),
        'id'       => 'test-blck',
        'fields'   => [
            [
                'id'   => $prefix . 'text_hdsmywqrchf',
                'type' => 'text',
                'name' => esc_html__( 'Text Field Test BLCK', 'text-domain' ),
            ],
            [
                'id'         => $prefix . 'taxonomy_advanced_yhwon6kcqb',
                'type'       => 'taxonomy_advanced',
                'name'       => esc_html__( 'Taxonomy Advanced Field', 'text-domain' ),
                'taxonomy'   => 'test-type',
                'field_type' => 'select',
            ],
            [
                'id'                => $prefix . 'text_ey3ewpvlke',
                'type'              => 'text',
                'name'              => esc_html__( 'Amount text field', 'text-domain' ),
                'size'              => 16,
                'columns'           => 12,
                'sanitize_callback' => 'xn_sanitize_money_field',
            ],
        ],
        'category' => 'layout',
        'icon'     => 'admin-appearance',
        'type'     => 'block',
        'mode'     => 'edit',
    ];

    return $meta_boxes;
}

This is my callback function defined in my functions.php:

function xn_sanitize_money_field ($value) {
        // Do something with $value.
        $number = floatval ( $value );
        $value_new = number_format ($number, 2, ",", ".");  
        return $value_new;
}

And this is my problem:
https://share.getcloudapp.com/OAuWJv9m