YOSSession not recognizing expired token?

I am just trying to get the sample "SocialSample" application running on my iPhone 4.0 sdk. I had it working fine (with the callback "hack") until the hour token expiration time passed. Now I keep getting the error:

{"error":{"lang":"en-US","description":"Please provide valid credentials. OAuth oauth_problem=\"token_expired\", realm=\"yahooapis.com\""}}

I have traced the code through the resumeSession method of YOSSession.m, but it seems like it is not correctly detecting that the session is expired.

Please help!

I am using the latest yos-social-objc SDK from github (1.0 dated 12/16/2009).