Orbeon Forms PE (Ehcache) replication without multicasting - replication

Question

We want to set up Orbeon Forms PE replication but we cannot use multicasting as proposed in the docs.
We have two nodes - 172.13.238.241 and 172.13.238.242 and the problem seems to be with the EhCache part. I open the form, load balancer (haproxy) directs me to a node, I turn of the second node and then for several minutes all the requests in the brower fail. Eventually the request start to work again but they are very slow.
This is what I have in node 1 (another node has same config with IP-s replaced with each other and it has a different uniqueId value):
<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"
channelSendOptions="asynchronous"
channelStartOptions="3">
<Manager className="org.apache.catalina.ha.session.DeltaManager"
expireSessionsOnShutdown="false"
notifyListenersOnReplication="true"/>
<Channel className="org.apache.catalina.tribes.group.GroupChannel">
<Interceptor className="org.apache.catalina.tribes.group.interceptors.StaticMembershipInterceptor">
<Member className="org.apache.catalina.tribes.membership.StaticMember"
port="4100"
host="172.13.238.242"
uniqueId="{0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,2}" />
</Interceptor>
<Receiver className="org.apache.catalina.tribes.transport.nio.NioReceiver"
address="172.13.238.241"
port="4100"
autoBind="0"
maxThreads="6"
selectorTimeout="5000" />
<Sender className="org.apache.catalina.tribes.transport.ReplicationTransmitter">
<Transport className="org.apache.catalina.tribes.transport.nio.PooledParallelSender"/>
</Sender>
<Interceptor className="org.apache.catalina.tribes.group.interceptors.TcpFailureDetector"/>
<Interceptor className="org.apache.catalina.tribes.group.interceptors.MessageDispatchInterceptor"/>
<Interceptor className="org.apache.catalina.tribes.group.interceptors.ThroughputInterceptor"/>
</Channel>
<Valve className="org.apache.catalina.ha.tcp.ReplicationValve" filter=".*\.gif|.*\.js|.*\.jpeg|.*\.jpg|.*\.png|.*\.htm|.*\.html|.*\.css|.*\.txt"/>
<ClusterListener className="org.apache.catalina.ha.session.ClusterSessionListener"/>
</Cluster>
I wonder if anyone could spot some mistakes in my ehcache configuration.