Register Nav Menus

Hi

I am experiencing a strange error when trying to update the name of a registered menu location in functions.php

This error only shows up when in debug mode: define(‘WP_DEBUG’, true);

So originally the name of the menu location was primary

register_nav_menus( array(
	'topbar_info' => __( 'Top Header Menu (Info)', '' ),
	'topbar_controls' => __( 'Top Header Menu (Controls)', '' ),
	'primary' => __( 'Main Menu', '' )
	) );

If I change the name from ‘primary’ to ‘menu-style1’

register_nav_menus( array(
	'topbar_info' => __( 'Top Header Menu (Info)', '' ),
	'topbar_controls' => __( 'Top Header Menu (Controls)', '' ),
	'menu-style1' => __( 'Main Menu', '' )
	) );

I get this error on the backend: Appeararance/Menus/Edit Menus:

Main Navigation( ! ) Notice: Undefined index: primary in C:\wamp\www\frank\wp-admin\nav-menus.php on line 627
Call Stack #TimeMemoryFunctionLocation 10.00271127856{main}(  )..\nav-menus.php:0 (, Main Menu)

If I turn debug off I don’t see the error. Not sure what I am doing wrong here any help is appreciated.

thanks