Unsubscribe on a valid pubsub subscription returns unexpected-request: not-subscribed

I interrogate Openfire for a list of my subscriptions. Note that 5GK790… is present in the list.

OUT:
  <iq id="7f460c8c-0ed7-4f74-b1fb-5dc783093593" to="pubsub.clarabel"
  type="get">
  <pubsub xmlns="http://jabber.org/protocol/pubsub">
  <subscriptions node="AI50202AV50202-LEON"></subscriptions>
  </pubsub>
  </iq>
  IN :
  <iq from="pubsub.clarabel" id="7f460c8c-0ed7-4f74-b1fb-5dc783093593"
  to="leon@clarabel/office" type="result">
  <pubsub xmlns="http://jabber.org/protocol/pubsub">
  <subscriptions node="AI50202AV50202-LEON">
  <subscription jid="leon@clarabel"
  subid="pxxI9qUj3B0SV37MfG5g56xlr7h3C2rp1jS9F1gS" subscription="subscribed"></subscription>
  <subscription jid="leon@clarabel"
  subid="5GK790Gr1Q0bAGfUY8N4jJ8LKysGbu5oyvx0aSBu" subscription="subscribed"></subscription>
  </subscriptions>
  </pubsub>
  </iq>

I then send an unsubscribe request to Openfire for that subscription:

<iq id="8ef8a961-53ae-4eb2-ac98-e237d6ad2572" to="pubsub.clarabel"
  type="set">
  <pubsub xmlns="http://jabber.org/protocol/pubsub">
  <unsubscribe jid="leon@clarabel"
  subid="5GK790Gr1Q0bAGfUY8N4jJ8LKysGbu5oyvx0aSBu" node="AI50202AV50202-LEON"></unsubscribe>
  </pubsub>
  </iq>

Received:

<iq from="pubsub.clarabel" id="8ef8a961-53ae-4eb2-ac98-e237d6ad2572"
  to="leon@clarabel/office" type="error">
  <pubsub xmlns="http://jabber.org/protocol/pubsub">
  <unsubscribe jid="leon@clarabel"
  subid="5GK790Gr1Q0bAGfUY8N4jJ8LKysGbu5oyvx0aSBu" node="AI50202AV50202-LEON"></unsubscribe>
  </pubsub>
  <error type="wait">
  <unexpected-request xmlns="urn:ietf:params:xml:ns:xmpp-stanzas"></unexpected-request>
  <not-subscribed xmlns="http://jabber.org/protocol/pubsub#errors"></not-subscribed>
  </error>
  </iq>

Any ideas?

I’m using Openfire 3.8.2.

I have the same problem with openfire 4.0.1.

Any suggestion?