Should I be able to use fast concurrent binding when using a global catalog? I've run into an issue where FCB only works when the binding user is in the same domain as the global catalog server. If I attempt to authenticate a user in a different domain, the global catalog server returns invalid credentials to my bind attempts. If I don't call SessionOptions.FastConcurrentBind() on my connection then the bind works fine for all users.
The connection used to test user logins is setup as GC over SSL, AutoBind=false, AuthType.Basic, and I'm verifying the server supports FCB prior to the first bind.