Few Users get Internal Server Error - 500 on EBS Asserter URL which gets autofixed on refresh

Summary:

Few Users get Internal Server error - 500 on EBS Asserter URL (while accessing OCI LB URL) which gets auto fixed on every browser refresh.

EBS Asserter Log has the below error.
ServletContext@1677403669[app:ebsext module:ebsext.war path:null spec-version:3.1]] Root cause of ServletException.
java.lang.IllegalArgumentException: Invalid sessionId found
at oracle.apps.fnd.util.PreCondition.assertTrue(PreCondition.java:68)

EBS on 12.2 , EBS Asserter is integrated with IDCS.

Any hint/help is much appreciated.