event_members (Facebooker::Session) only actually talks to facebook the first time you use it, no matter the eid. I
think the problem is here:

@members ||= post('facebook.events.getMembers', :eid => eid) do |response|

I think that should be @members = post .... instead. Anyway, if I change it to that, it fixed the problem. However this
means that if you ask for the members of the same event multiple times, you will waste a lot of time. I don't know what
the proper solution is. But that's a workaround.