pgmb_gravity_forms_fields.php

<?php

function pgmb_gf_post_created($post_id, $feed, $entry, $form){
	global $post_to_google_my_business_plugin;

	$post_type = 'your_post_type';

	// -- Do not edit after this

	//If this is a different post type, abort
	if($post_type != get_post_type($post_id)){
		return;
	}

	//Make sure the snippet doesn't crash the site if the plugin is disabled or the name of the variable is changed
	if(!isset($post_to_google_my_business_plugin) || !$post_to_google_my_business_plugin instanceof MBP_Plugin){
		return;
	}

	$reflection =  new ReflectionObject($post_to_google_my_business_plugin);
	try{
		//Make sure the metabox property actually exists
		$metabox = $reflection->getProperty('metabox');
	} catch (ReflectionException $ex) {
		return;
	}

	$metabox->setAccessible(true);
	$instance = $metabox->getValue($post_to_google_my_business_plugin);

	//Cancel the default auto post
	add_filter('mbp_autopost_before_insert_subpost', '__return_false');

	$instance->save_autopost_template($post_id, get_post($post_id), false);
}

add_action( 'gform_advancedpostcreation_post_after_creation', 'pgmb_gf_post_created', 10, 4 );