Admin toolbar indicates a different subsite than where this page actually lives

I have a page with the shortcode [eab_calendar network="yes"]. This page lives on the main site of a multisite network. When I visit the page, the admin toolbar says we're on a subsite of the network, and there is no "Edit Page" button.

I am trying to troubleshoot this, and I just can't figure out where to look. I've been flipping plugins off, testing alternate themes, etc, and I haven't made any progress.

I am hoping that someone can give me some information about where to look for the cause. It would help to understand what exactly triggers the admin toolbar, and what sort of plugin might be responsible.

Thanks for any suggestions.