Stopped cluster members is out of sync when coming back

We have 3 servers setup in cluster mode. The configuration has been tested ok: making one configuration on one node is taken into account on the other node. What we are noticing is that after some time, node stop being in sync: one modification on a node is not taken into acount on the other node anymore. It seems that the page is still in cache when it should have been reloaded.

Some info about the configuration:

• XWiki 2.6
• jgroups-2.11.0.GA.jar
• in xwiki.properties observation.remote.enabled = true
• in xwiki.properties observation.remote.channels = tcp1
• tcp.xml attached