I found out a little bit more. They purchased their membership (which provides access to particular pages) using a coupon code that brings their cost to 0. When I login as this member (that purchased via the coupon code) I can't get to the members only pages. But, when I log in as a member that purchased via a credit card, I can get to the pages.
Even more info, if the person completed the purchase in September (that's one that we tested) using the same coupon code that took their purchase to 0, logging in as that person, I can access those member pages as they are supposed to. The person that made the purchase using the coupon code (and we verified that the purchased item was correct) purchased the product on November 17.
We've tried a few different people and scenarios and am finding it may be just that one person having problems - the one with the November 17 purchase. All others appear to work, as we are looking through and testing this.
Let us know if you need any other information.