I've had this problem for a while now and even after using the 1.5 DLLs it's still occuring. Basically when a user returns to my application the 2nd or 3rd post back to the server causes it to re-log them in. After that is works fine. It's as though their
session is still active and only after the first few requests does it go back to Facebook for login details or something. I'm using the standard setup of the Service and am not doing anything fancy with the service itself... i.e.
new protected void Page_Load(object sender,
base.Api = this.Master.Api;
base.Secret = this.Master.Secret;
If anyone has suggestions or knows of a fix I'd love to hear it!!!