Run the Case Summary Table report with the second vertical group selected with a value.
The drill down of the Horizontal Total, i.e. the last column, gives me a list of cases more than what I expect.
See if there is a fix out there.
Thanks Joel.
I found the link below. That solves my problem.
http://support.microsoft.com/kb/945910
I have tested the report, and it works as it should.
Check your default filters on the report. Also, are you sure that no one has modified the drillthrough report?