UtilSession failed: Error in checking for identical patches for composite patch

Yesterday while applying the April 2018 PSU, we encountered the below error:

host01> $ORACLE_HOME/OPatch/opatch apply 
Oracle Interim Patch Installer version 11.2.0.3.6 
Copyright (c) 2013, Oracle Corporation. All rights reserved. 

Oracle Home : /u01/sq/DB01/db/11.2.0.4 
Central Inventory : /opt/oraInventory/oraInventory 
from : /u01/sq/DB01/db/11.2.0.4/oraInst.loc 
OPatch version : 11.2.0.3.6 
OUI version : 11.2.0.4.0 
Log file location : /u01/sq/DB01/db/11.2.0.4/cfgtoollogs/opatch/opatch2018-04-24_12-19-05PM_1.log 

Verifying environment and performing prerequisite checks... 
UtilSession failed: Error in checking for identical patches for composite patch. This means a constituent to be applied has an earlier creation date than a constituent installed in the Oracle Home. This patch is improperly packaged and will not be applied. 
Log file location: /u01/sq/DGRIDO01/db/11.2.0.4/cfgtoollogs/opatch/opatch2018-04-24_12-19-05PM_1.log 

The message which it was showing was completely clueless. From the error message it is very difficult to get the root cause of this error.

So we raised a case with Oracle and they suggested to use the latest OPatch version to resolve the issue. Though we had valid OPatch version, we replaced it with the latest one and the issue was resolved.