Data Import Wizard Invalid Lookup Value

Summary

Does data Import Wizard allow importing when aggregation relationship is applied?

Content

Hello,

We are trying to import data into new custom objects using the Data Import Wizard.  It imports all the data tables just find from parent to child when they have an association relationship.  However, when the relationship between the parent and the child has an aggregation relationship, the data import wizard throws an "Invalid Lookup" value for al of the parent foreign keys in the child table, even though they are valid IDs from the parent table.  Is this a bug or is it functioning as it is supposed to?