The following exception is thrown when a list with a formula field is being copied:
An error occurred while copying field '<Field Name>'.
Cannot add field '<Field Name>'. The formula refers to a column that does not exist. Check the formula for spelling mistakes or change the non-existing column to an existing column.
at Metalogix.SharePoint.Adapters.CSOM2013.CSOMAdapter.AddFieldToCollection(ClientContext ctx, List parentList, XmlNode fieldNode, FieldCollection& fields, String displayName, String internalName)
at Metalogix.SharePoint.Adapters.CSOM2013.CSOMAdapter.AddFieldsXML(ClientContext ctx, List parentList, FieldCollection fields, XmlNode fieldNodeXML, Boolean bUpdateFieldTypes, OperationReporting reporting)