We were having this issue with one of our reports where the parameter length was huge and therefore the drill functionality was breaking the report with error "Invalid URI: The Uri string is too long".
After searching around the fix it was available for SP1 Cumulative Update (CU) 8. Unfortunately the SP1 is retired and therefore I installed the latest service pack (SP3) with all the latest CU3 but the issue is still there.
I was wondering if anyone knows how to correct this issue. I have been searching around but can't seem to find the answer. Thanks in advance!