Pivot misses a row

I have a data table (160 Rows * 28 Columns) which I want to condense by using a pivot table.
All works well at first until I had to edit one item of the data set in the column containing the items used by the pivot to sum the data. When I refreshed the pivot, the edited item and the data it referencing was missing.
The attached workbook shows a selection from the data table including the edited row (tc in ColK). But here the pivot table has not missed out tc.
Seeing this I went back to the full data set and ran another identical pivot to the original and again tc was missing.
What is happening here? I have presumed it is something to do with editing tc but does that mean that I will have to set up a new data table, and pivot that anew?
John