Can't Preview Unpublished Pages with Multiple Contexts

I've been working on a site with multiple contexts ( 2 active at present, but looking to add 2 more over the next few weeks/months for 4 total contexts). Both are behaving fairly well, but today I noticed something peculiar with the secondary (i.e. non-'web') context.

If I am logged into the manager and working in the main 'web' context, I can create pages, and view the unpublished pages in the front end. If I'm logged out, of course, these unpublished pages aren't visible.

However, in my secondary context, when I attempt to view an unpublished page, I get forwarded to the site's error page. Under access controls, I've added context access for my administrator group (Access policy 'Administrator' for 'Super User'). Any ideas here? Nothing showing up in the error logs and everything else seems to be working as expected.

Am I missing a step/setting?