By the way when the "Meta Box Updater" plugin is activated I get the admin notice "Warning! You have not set your Meta Box license key yet..." on the entire network. I think you should check for a super admin capability when it's installed on a multisite.
Please do more checks on multisite. Meta Box plugin and all extensions should be fully compatible with multisite.
You're right. For multisite, the settings page should be put in the network admin instead of each site's admin and the license key should be stored in the network options. I didn't think about this at first. Let me try to update the plugin.
PS: Just updated the plugin to support multisite. In Multisite environment, the settings page is moved to Network > Settings > Meta Box Updater. Normal site admins won't see the message and that settings page. Please update and let me know how it goes.
PS2: Your license for Core extension bundle is expired. Please update to get updates for other plugins.