Data export format changed after adding Date Last Refreshed card

I'm now having formatting issue when I choose "data export" on the web.  I added a "last refreshed date" card to my report, using the following query:

let

Source = #table(type table[Date Last Refreshed=datetime], {{DateTime.LocalNow()}})

in

Source

Now (in the data export) the column headings are different, I've lost the filtered headings and row coloring, and at the bottom is this line:

Applied filters:Device Type is Smart PhoneIntune Enrollment is Not enrolled into IntuneCarrier is not Cellhire USADescription does not contain 'PERSONAL'Assigned_Profile is (Blank) or Corporate iOS Device EnrollmentExclusion List.Exclude is not X