Error when I try to create a "Manage employment" approval rule

Summary:

Error when I try to create a "Manage employment" approval rule

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Hi,

we would like to configure the 'Manage employment' approval rule. The approver has to be the worker's supervisor (not the Line Manager but another custom supervisor type). We already identified this kind of approver in the Performance document approval rule. In this case, we selected a 'Management Hierarchy' approver type. The Starting Participant and the Top Participant (see the screenshot 'PERF_DOC_APPROVAL_RULE') have been identified in this way: we selected the Get User option; as Reference User we entered this formula: GetManager("MON_HRBP",Task.payload.Worker's Assignment.result.requestManager), where MON_HRBP is the Lookup code related to our custom supervisor Type. With this configuration our Performance document