Unable to undo checkout for CAD Document with error in Event Manager 'The object was improperly initialized (i.e., it was null)' in Windchill PDMLink

• User and administrators are unable to perform undo checkout for a specific CAD Document
• Cannot delete object or undo checkout from user workspace
• Event Manager has the following error

The object was improperly initialized (i.e., it was null)
INFO  : com.ptc.windchill.uwgm.proesrv.StandardRequestDispatcher wcadmin - StandardRequestDispatcher.dispatchRequest ::  >   UWGM request: UnlockIterations_i
INFO  : com.ptc.windchill.uwgm.proesrv.action.UnlockIterationAction wcadmin - UnlockIterationAction.executeAction :: Begin Unlock Iterations ...
ERROR : com.ptc.windchill.uwgm.proesrv.action.UnlockIterationAction wcadmin - UnlockIterationAction.executeAction ::
(wt.vc.wip.wipResource/0) wt.vc.wip.WorkInProgressException: The object was improperly initialized (i.e., it was null).
at wt.vc.wip.StandardWorkInProgressService.validateAccessForUndoCheckout(StandardWorkInProgressService.java:2897)
at wt.vc.wip.StandardWorkInProgressService.undoCheckouts(StandardWorkInProgressService.java:1102)
at sun.reflect.GeneratedMethodAccessor4127.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at wt.services.ServiceFactory$ServerInvocationHandler.invoke(ServiceFactory.java:314)
at $Proxy33.undoCheckouts(Unknown Source)
at com.ptc.windchill.uwgm.proesrv.action.UnlockIterationAction.executeAction(UnlockIterationAction.java:70)
at com.ptc.windchill.uwgm.proesrv.request.UnlockIterationsRequest.executeRequest(UnlockIterationsRequest.java:91)
at com.ptc.windchill.uwgm.proesrv.StandardRequestDispatcher.dispatchRequest(StandardRequestDispatcher.java:1001)
at com.ptc.windchill.uwgm.proesrv.StandardRequestDispatcher.scanRequests(StandardRequestDispatcher.java:862)
at com.ptc.windchill.uwgm.proesrv.UwgmTransactionExecuterImpl.execute(UwgmTransactionExecuterImpl.java:94)
at com.ptc.windchill.uwgm.proesrv.UwgmTransactionExecuterImpl.executeTransaction(UwgmTransactionExecuterImpl.java:56)
at com.ptc.windchill.uwgm.proesrv.ProeService.executeTransaction(ProeService.java:102)
at com.ptc.windchill.uwgm.proesrv.ProeService.execute(ProeService.java:80)
at com.ptc.windchill.uwgm.cadx.request.UwgmRequestProcessor.process(UwgmRequestProcessor.java:45)
Stacktrace from 10.0 M020