Tomcat's Clustering / Session Replication not replicating properly

We had this identical issue. Although not documented anywhere, what solved it for me was to simply move the <Manager> tag from server.xml to the global context.xml (bringing it out of the <Server>...<Cluster>... group and into the <Context> group). As soon as we did this, everything "magically" began working. This only applied to Tomcat 7...Tomcat 6 worked perfectly with the setup you describe above (and as the documentation describes).

<Context>
    <Manager className="org.apache.catalina.ha.session.DeltaManager"
             expireSessionsOnShutdown="false"
             notifyListenersOnReplication="true" />
</Context>

Now just remove the <Manager> tag from your Cluster group in server.xml and you're done.

on server.xml just add:

<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"
             channelSendOptions="6"/>  

and, in your context.xml:

<Manager className="org.apache.catalina.ha.session.DeltaManager"
         expireSessionsOnShutdown="false"
         notifyListenersOnReplication="true" />

it worked for me, i'm using Tomcat 7 and Tomcat 8