I installed the recently released CU 4 for sp1 because it resolved a problem we were seeing with SSIS packages calling other SSIS packages producing a nebulous "unexpected termination".
The good news is that our "unexpected termination" problem went away. The bad news is that our SSRS reports with parameter lists stopped working, i.e. they didn't render the report.
When I turned on a trace, and started the report I could see the stored procedure calls that populated the parameter lists so I know it at least started to execute. When I selected my parameters to submit to the query and clicked the "Submit" button nothing happened. A brief flash of the green "loading" circle and that was it. The report stored procedure that used those parameters was never called according to my trace so it seems relatively clear that some sort of disconnect is occurring.
When I uninstalled CU 4, the reporting problem went away.
Now I have a chicken and egg problem. If I don't install CU 4, I can't run my ETL and if I do, I can't run my reports.
I've submitted this as a bug to Microsoft Connect but I'm wondering if anyone else has noticed this behavior.
"Beliefs" get in the way of learning.