Returning collection from function -- need to access field value before returning, otherwise empty?

I have a function in appA that returns a collection. In appB I am executing the function and attempting to read the values from the fields. If I simply iterate over the records and insert then into the return collection, when I try to read the field values they are empty. I need to access at least one field in the record prior to inserting the record into the returned collection in order to populate the fields. It seems that simply doing a temp = record.getFieldValue("some_field") is sufficient for now.

Is this correct? Is it because I am calling cross-application? Or is it documented somewhere? Will this work if I have a subform, i.e. will the subform values be populated, or will I need to loop through those one-by-one?