=GETPIVOTDATA returning #REF! when using '=' to pull value through to another cell?

Hi All

Can anyone offer any advice as to why =GETPIVOTDATA() would return #REF! ?
All I'm doing is entering an '=' into the destination cell then clicking the item in the pivot I wish to return

For example this formula works
=GETPIVOTDATA("Case Number",$L$21,"Work Type","IMA","State2","DNA")

But if I use the column label filter button to change pivotfield 'State2' from "DNA" to "Attended" then repeat the above process it returns #REF! for every column except the grand total?
=GETPIVOTDATA("Case Number",$L$21,"Work Type","IMA","State2","Attended")

Am I doing something really silly?
Any/all advice welcome

Many thanks
V

Ah ok, that's interesting.

So if I remove State2 from the column labels it works
And I notice that State2 isn't actually a column in the dataset sheet so I wonder where the info for the pivots is coming from, must be the pivot cache?

At least I know where the problem lies now
Thank you