UpdateAceStatus worker not serializable, fails in redis cluster mode

015-08-17 12:55:00,139 WARN  [Nuxeo-Work-updateACEStatus-1] [Transaction] Unexpected exception from afterCompletion; continuing
java.lang.RuntimeException: java.io.NotSerializableException: com.codahale.metrics.Counter
        at org.nuxeo.ecm.core.redis.contribs.RedisBlockingQueue.putElement(RedisBlockingQueue.java:92)
        at org.nuxeo.ecm.core.work.NuxeoBlockingQueue.put(NuxeoBlockingQueue.java:85)
        at org.nuxeo.ecm.core.work.NuxeoBlockingQueue.offer(NuxeoBlockingQueue.java:68)
        at org.nuxeo.ecm.core.work.NuxeoBlockingQueue.offer(NuxeoBlockingQueue.java:33)

    protected void fireACEStatusUpdatedEvent(List<DocumentRef> docRefs) {
        EventContext eventContext = new EventContextImpl(session);
        eventContext.setProperty(DOCUMENT_REFS, (Serializable) docRefs);
        eventContext.setProperty(REPOSITORY_NAME, session.getRepositoryName());
        Framework.getService(EventService.class).fireEvent(ACE_STATUS_UPDATED, eventContext);
    }