Regardless of rules, single post urls not accessible to ANY account levels

I cannot seem to get any of the blog posts to display on their single post url permalink, either for public users or logged in members, regardless of logged in status, category rules, or post rules. Viewing the category page post snippets seems to work fine and according to rules, but as soon as I click the "read more" button, which links to the post permalink url, I am redirected to the members-only page.

The ONLY way I have been able to see single posts is to delete ALL rules for categories and/or posts, and simply leave them out of the rules, which is making them available for all levels, both free and membership.

Additional observations for troubleshooting:

I am using a pretty permalinks structure as follows : %category%/%postname%

Only when logged in to my admin account am I able to see the single post pages (when any category rules are applied)

I am currently using the following plugins:
Dropdown Menu Widget by shailan.com
Membership Premium 3.0 with recent patch applied
Maintenance Mode
Akismet
WPMU DEV Updates

Any ideas?