Prohibit self approval not working in learning request approval in BPM

Summary:
When manager is requesting a non-catalog item for his direct report, there is an approval flow which goes like:

Manager(Submitter)=Representative-> CHRO(Approval Group)

There are case in which the person who is in approval group is also a manager when he submit the request , it should skip him. so I used Prohibit self approval in BPM with below task payload attribute:

/task:task/task:payload/ns3:getRequestorInformationByUserName/ns3:userName

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