get property ‘ID’ of non-object

On my 404 pages I get the following error:

Notice: Trying to get property ‘ID’ of non-object in /home/dogtotzs/public_html/wp-content/plugins/easy-image-gallery/includes/gutenberg-block/src/init.php on line 40

The related function looks like this:

function easy_image_gallery_hide( $post_id ) {

	$post_types = easy_image_gallery_allowed_post_types();

	$post_type  = get_post_type( $post_id );

	if ( ! array_key_exists( strval( $post_type ), $post_types ) ) {

		return true;

	}

	return false;

}