SSRS 2008 Interactive Sorting in Sub-Report not working as expected

I have a (parent) report that has a list. The details group of this list contains one sub-report. So basically if the list has 10 records (rows) the sub-report is executed 10 times.

The problem seems to be with interactive sorting in the Sub-Report. It has 4 columns with interactive sorting enabled. When I run the parent report and try to sort columns SSRS "remembers" the previous sort column and sorts by multiple columns at the same time. For example if I sort by Col A then click to sort by Col B, SSRS will preserve the sorting o开发者_如何学Gof Col A (and the direction) and then apply the sorting to Col B. However I simply want to sort by Col B and do not want to Col A to be part of the sort.

When I try this directly with the sub-report everything works as expected.

Any ideas why this is happening?

This is a potential bug in SSRS 2008. I used a table instead of a list in the parent report and everything is now working correctly. Go figure!