a required component is missing in the jcr config of GateIn 3.2 and EPP 5.2 which is the RPCService that is used by the JCR in cluster environment to allow cluster nodes to communicate.  See below an example of how to configure it:

  <component profiles="cluster">
    <key>org.exoplatform.services.rpc.RPCService</key>
    <type>org.exoplatform.services.rpc.impl.RPCServiceImpl</type>
    <init-params>
      <value-param>
        <name>jgroups-configuration</name>
        <value>${gatein.jcr.jgroups.config}</value>
      </value-param>
      <value-param>
        <name>jgroups-cluster-name</name>
        <value>RPCService-Cluster</value>
      </value-param>
      <value-param>
        <name>jgroups-default-timeout</name>
        <value>0</value>
      </value-param>
    </init-params>
  </component>

This should be added in gatein.ear/02portal.war/WEB-INF/conf/jcr/jcr-configuration.xml. More details about it here http://docs.jboss.org/exojcr/1.14.6-GA/developer/en-US/html_single/#Kernel.RPCService.