Custom theme add_meta_boxes action seems to override “siteorigin_panels_metaboxes” metabox callback

Hello together,

we are currently setting up a custom theme that uses the page builder.
Our theme has some metaboxes for pages/posts in the sidebar area with settings for the page/post.

After long debugging I came to the conclusion that the “add_meta_boxes” action in our theme somehow affects/overrides the action from the Page Builder. If I delete the action from the theme everything works fine.

The problem is that the Page Builder always reverts to WP-Editor mode after saving the post.
I cannot say why the breaking point seems to be there. The metabox from the Page Builder seems to be added normally, just the callback function gets overridden/not called.

Does anyone know where this could come from? The call to the theme meta boxes is in a class and the callback is added as follows:

//add meta box action
public function __construct()
{
    add_action( 'add_meta_boxes', array($this, 'defaultMetaBoxes') );
}

public function defaultMetaBoxes() {
    add_meta_box(
	'drowtheme_breadcrumb',
	__( 'Options', 'drowtheme' ),
	array($this, 'metaboxCallback'),
	array('post', 'page'),
	'side',
	'high'
    );
}

Normally, since we initialize the hook within the class context, there should be no problem.
Sadly I am stuck with this and cannot find a solution so I would be very happy if someone could help.

EDIT:
We have found the solution. The problem was that in our metabox callback we had a WP_Query.
The problem was that the WP_Query had overridden the globaled $post object.

To avoid further problems with this I would recommend to the plugin authors to delete the globaled $post from the following function:

function siteorigin_panels_get_current_admin_panels_data( ){
	$screen = get_current_screen();

	// Localize the panels with the panels data
	if($screen->base == 'appearance_page_so_panels_home_page'){
		$home_page_id = get_option( 'page_on_front' );
		if( empty($home_page_id) ) $home_page_id = get_option( 'siteorigin_panels_home_page_id' );

		$panels_data = !empty($home_page_id) ? get_post_meta( $home_page_id, 'panels_data', true ) : null;

		if( is_null( $panels_data ) ){
			// Load the default layout
			$layouts = apply_filters( 'siteorigin_panels_prebuilt_layouts', array() );

			$home_name = siteorigin_panels_setting('home-page-default') ? siteorigin_panels_setting('home-page-default') : 'home';
			$panels_data = !empty($layouts[$home_name]) ? $layouts[$home_name] : current($layouts);
		}
		elseif( empty( $panels_data ) ) {
			// The current page_on_front isn't using page builder
			return false;
		}

		$panels_data = apply_filters( 'siteorigin_panels_data', $panels_data, 'home');
	}
	else{
		global $post;
		$panels_data = get_post_meta( $post->ID, 'panels_data', true );
		$panels_data = apply_filters( 'siteorigin_panels_data', $panels_data, $post->ID );
	}

	if ( empty( $panels_data ) ) $panels_data = array();

	return $panels_data;
}

Instead you can use the post parameter that is already passed to the metabox callback like here (Example from the WP Doc):

/**
 * This function adds a meta box with a callback function of my_metabox_callback()
 */
function add_wpdocs_meta_box() {
    $var1 = 'this';
    $var2 = 'that';
    add_meta_box(
        'metabox_id',
        __( 'Metabox Title', 'textdomain' ),
        'wpdocs_metabox_callback',
        'page',
        'normal',
        'low',
        array( 'foo' => $var1, 'bar' => $var2 )
    );
}

/**
 * Get post meta in a callback
 *
 * @param WP_Post $post    The current post.
 * @param array   $metabox With metabox id, title, callback, and args elements.
 */

function wpdocs_metabox_callback( $post, $metabox ) {
    // Output last time the post was modified.
    echo 'Last Modified: ' . $post->post_modified;

    // Output 'this'.
    echo $metabox['args']['foo'];

    // Output 'that'.
    echo $metabox['args']['bar'];

    // Output value of custom field.
    echo get_post_meta( $post->ID, 'wpdocs_custom_field', true );
}

Kind regards
Patrick