Feedback after error event COMPLETEDAPPRAISAL of BUS7026

Hi All,

I activated standard Appraisal approval workflow WS01000105.

When I complete an appraisal document and event COMPLETEDAPPRAISAL of BO BUS7026 is triggered I check event trace and see FEEDBACK ERROR saying "Source (expression '&_EVT_OBJECT.AGGREGATE&') of binding assignment is not available"

I am not very sure where to look for the problem. Since the WF, BO everything is standard what could have gone wrong?

Thanks in Advance!