Unable to retrieve agile sprints events when second node joins the cluster

2014-05-10 22:50:42,682 ERROR [http-80-13] [extra.calendar3.rest.CalendarResource] getEvents Unable to load events of sub-calendar b46d662b-b919-4b4f-b7b3-3ac4a522e879,.
 -- url: /rest/calendar-services/1.0/calendar/events.json | userName: xxx | referer: <URL>//calendar/mycalendar.action
(Wrapped) java.io.NotSerializableException: com.atlassian.confluence.extra.calendar3.calendarstore.DefaultJiraAccessor
2014-05-10 22:50:42,690 ERROR [http-80-13] [jersey.spi.container.ContainerResponse] logException Mapped exception to response: 500 (Internal Server Error)
 -- url: /rest/calendar-services/1.0/calendar/events.json | userName: xxx | referer:<URL>/calendar/mycalendar.action
javax.ws.rs.WebApplicationException

2014-05-11 19:46:33,362 ERROR [Logger@9257178 3.3.1/389] [Coherence] log 2014-05-11 19:46:33.362 Oracle Coherence GE 3.3.1/389 <Error> (thread=ReplicatedCache, member=1): An exception (java.io.NotSerializableException: com.atlassian.confluence.extra.calendar3.calendarstore.DefaultJiraAccessor) occurred while serializing Lease: 8a8f83ae457910740145791a792309d6:54b00e00-e8f8-4571-9299-7162e480bdb5:jira://56f62595-ae02-3808-8d94-2809a6a71910?projectKey=TESTTTT&dateFieldName=sprint (Cache=com.atlassian.confluence.extra.calendar3.calendarstore.generic.AgileSprintsSubCalendarDataStore:subcalendar-data, Size=Unknown, Version=0/3, IssuerId=1, HolderId=0, Status=LEASE_AVAILABLE, Last locked at Sun May 11 19:46:21 KST 2014) for CacheHandler{Name=com.atlassian.confluence.extra.calendar3.calendarstore.generic.AgileSprintsSubCalendarDataStore:subcalendar-data, Index=97, ServiceName=ReplicatedCache, ClassLoader=WebappClassLoader
  context:
  delegate: false
  repositories:
    /WEB-INF/classes/
----------> Parent Classloader:
org.apache.catalina.loader.StandardClassLoader@2d97c1b1
}
2014-05-11 19:46:33,366 ERROR [Logger@9257178 3.3.1/389] [Coherence] log 2014-05-11 19:46:33.362 Oracle Coherence GE 3.3.1/389 <Error> (thread=ReplicatedCache, member=1):
java.io.NotSerializableException: com.atlassian.confluence.extra.calendar3.calendarstore.DefaultJiraAccessor