Smart Report Fields

Have saved Smart report that has been working, the report included 4 fields for Billing Description Line1,2,3,4.  Report will now not produce any records but if I remove these four fields I get the records I expect.  When I go back to add these fields the "Type" indicates "not Defined".  Not sure if this was always the "type" for this field or if something has changed.  Any ideas.  Thanks