Error when setting the rule for specific grade in Global Absence Single assignment transaction

Summary:

Hi,

I received below error when I setup a condition to exclude a specific grade from the approval rule.

Error Message:

ORABPEL-30006 exception.code:30006 exception.type: ERROR exception.severity: 2
exception.name: Error in getting manager of user.
exception.description: The manager of user XXXXXX could not be retrieved for the task 493810.
The task belongs to the workflow default/HcmGblAbsencesRecordingApprovalComposite!11.13.24.07.0/AbsencesApprovalsTask.
exception.fix: Make sure that user XXXXXX is valid and that the manager for user XXXXXX is defined

Rule Condition:

Rule 1: ( Task.payload.getRequestorInformationByUserNameResponse.result.gradeCode == "GEXD" ) > Self Auto Approve

Rule 2: (getRequestorInformationByUserNameResponse.result.gradeCode != "GEXD") > Management Hierarchy (LM Approval)