Drill through issue - Conditional Blocks

[cognosun]

We are using 8.4 , Oracle 10.2

We have a Report Studio report which has drill through option to a child report.

Child report has 'conditional blocks' in it.

The issue we are facing is, if we click on a link ( in parent report) ideally it should give us respective conditional block's data ( in child report )...but here what ever parent link we select ( from parent reprot ) , we are getting all the blocks from child report......this is not happening in one envrionment, but occuring in another environment.

Can anyone help.