Redirect to Parent Post of Child after edit.

Hi Warren,

You can try to get the connected post (parent project) based on the post ID (project entry) in the callback function. And redirect to the connected post by ID.

Something like:

add_action( 'rwmb_frontend_after_process', function( $config, $post_id ) {
    if ( 'my-meta-box' === $config['id'] ) {
        $pages = MB_Relationships_API::get_connected( [
            'id'   => 'project-entries_to_projects',
            'from' => $post_id,
        ] );

        $p = reset( $pages );
        wp_safe_redirect( get_the_permalink( $p->ID ) );

        die;
    }
}, 10, 2 );

Read more on the documentation https://docs.metabox.io/extensions/mb-relationships/#getting-connected-items
https://docs.metabox.io/extensions/mb-frontend-submission/#form-hooks