Non admin account can't update plugins

I'm trying to allow both user ID 1 and 2 to update WPMUDEV plugins (both are administrator level users). I added this to my wp-config.php:

define('WPMUDEV_LIMIT_TO_USER', '1, 2');

But the other user still isn't able to update plugins despite that. The admin user can, but now they're up to date, so I can't really test to see if the other user can after a change, so I'm not quite sure what to do. Also I don't have any change I could make to try to get it to work anyway.