Mandatory Header not working in Target xml in datahub

Hi All,

We have mandatory attributes in Product in hybris so made them as mandatory header - true in Target xml for product in datahub. But when we don't pass value for those attributes then we are getting impex error at hybris end not at datahub end.

As we already mentioned mandatory header for those attributes, we are expecting errors should be thrown at datahub end not at hybris.

                 <item>
                     <type>TargetPIMProduct</type>
                     <description>Hybris Platform representation of Products</description>
                     <updatable>true</updatable>
                     <canonicalItemSource>CanonicalProduct</canonicalItemSource>
                     <status>ACTIVE</status>
                     <dependencies>
                             <dependency>TargetWeightUnitEnum</dependency>
                             <dependency>TargetDimensionUnitEnum</dependency>
                     </dependencies>
                     <attributes>
                         <attribute>
                             <name>catalogNumber</name>
                             <localizable>false</localizable>
                             <collection>false</collection>
                             <transformationExpression>catalogNumber</transformationExpression>
                             <exportCode>catalogNumber</exportCode>
                             <mandatoryInHeader>true</mandatoryInHeader>
                         </attribute>
                     </attributes>
                 </item>

Any pointers on this issue ?