Membership w/free subscription does not remain logged in when signing up


I've got a membership site, which is our first deployment using a free subscription level

When you attempt to sign up for a subscription, if you create an account during the process, the account is created, but does not remain logged in.

If you are already logged in, and subscribe, everything works normally.

Our primary use case is new members signing up and paying in the same session, so any assistance you can provide in resolving this issue is appreciated.

I am currently running the most up-to-date versions of wordpress and membership (WP3.5.1,M3.4.4.1). The behaviour still occurs using M3.3.x.x.