If I modify a mapping in test to reproduce your mapping, I see no problem.
Here is the modified mapping from Order.xml
<
resultMap id=" order-with-dyn-favourite-line-item" class=" Order"><!--<result property="Id" column="Order_ID"/>
<result property="Date" column="Order_Date"/>
<result property="CardExpiry" column="Order_CardExpiry"/>
<result property="CardType" column="Order_CardType"/>
<result property="CardNumber" column="Order_CardNumber"/>
<result property="Street" column="Order_Street"/>
<result property="City" column="Order_City"/>
<result property="Province" column="Order_Province"/>
<result property="PostalCode" column="Order_PostalCode"/>-->
<result property="FavouriteLineItem" column="Order_ID=Order_ID,LineItem_ID=Order_FavouriteLineItem " select="GetDynSpecificLineItem " />
</resultMap>
