You are seeing updates in Microsoft Dynamics to a field named Birthmark but do not see the field in your Marketo instance.
The Birthmark field indicates whether the lead was created in Marketo or MS Dynamics. If the Birthmark field is blank, the lead would be a CRM-created record. If the Birthmark field contains the value 'mkto', then the record was created in Marketo.
Who This Solution Applies To
Microsoft Dynamic Users