We understand that there is clearly a problem on your end, but please understand that the information you've provided so far is not sufficient for us to make a test scenario on our end that would effectively help us pinpoint this one out. In all of our previous replies we ask for a sample project which would make this task a breeze. Note that we do not need your exact data, any test data that exhibits the problem would suffice.
We also need exact settings (OS, IIS, Application Pool type, .NET framework, type of application etc.), setup of the report (i.e. 2 parameters, 4 groups, aggregates etc) and full steps to reproduce (1. click here, 2. select this etc.).
Since this is a forum thread and you cannot attach projects here and if you provide a link it would be visible for other community members, it would be best if you open a ticket with all of the information we asked for. Once we create a test scenario and replicate the problem on our end, we would be able to provide more information on it or issue a hotfix for the problem
Looking forward to your reply.
the Telerik team