"3205 'XXXXXX' Is Not A Valid Role Or User Name"on 12.1.3 (But NOT on 11i)

Hi Experts,

Could you please advice on this ?

Customer on EBS 12.1.3, when operating the following steps , then met an error "3205 'XXXXXX' Is Not A Valid Role Or User Name"

(1) Employee A -> Approver B

(2) Employee A retirement

(3) Approver B return back to A  (using API wf_engine.SetItemAttrText() )

    ->  Error occur.

Is it an expected behavior?

If YES, why there was no such error on EBS 11i?

Confirmed the following source version with the customer.

------------------------

OWNER NAME TYPE LINE TEXT

APPS WF_ENGINE PACKAGE 2 /* $Header: wfengs.pls 120.6.12010000.3 2012/09/28 22:06:38 alsosa ship $ */

APPS WF_ENGINE PACKAGE BODY 2 /* $Header: wfengb.pls 120.25.12010000.17 2014/09/09 00:17:09 alsosa ship $ */