Criteria1 won't work with dates?

Hi all, i got a data table with filters.

when i try to get filter criteria for a non-date field with the following code all is ok

Dim lo As ListObject
Set lo = Worksheets("xxx").ListObjects("yyy")
if lo.AutoFilter.Filters(12).on = True then
   txt = lo.AutoFilter.Filters(12).Criteria1
end if

but when i try to get the same info for a date field i am getting Application defined or object defined error on the last line

lo.AutoFilter.Filters(12).on

returns True but .Criteria1 gets this error

any ideas??