unsubscribe links just loads the newsletter page

Hi,

Problem

I have carried out the following steps:
set up a newsletter
My permissions are set to allow anonymous subscriptions.
The newsletter has a 'single' opt in/out method.
mass subscribed an existing test user's email to the newsletter
sent out a single version of the newsletter [via cron].

The unsubscribe link in the email footer has the following:
http://www.example.com/newsletter/confirm/remove/274452a3c35t3123

Which just loads up the original newsletter content. eg
http://www.example.com/newsletter

The manage link http://www.example.com/newsletter/subscriptions shows that the user is still subscribed.

Have I missed something in the set up? Or is there actually a problem?

thank you
ice70