I wonder if this is related to this known issue:
If not, it would be good to write a simple test case to prove the failure and submit it on a JIRA ticket (you can use the attachment to the above issue as an example of how to submit a test case).
Jeff Butler

On 2/9/07, Tim.Hammar@mcnichols.com <Tim.Hammar@mcnichols.com> wrote:

Greetings all,

I have a complex query whose result set is mapped to resultMaps several levels deep by using the groupBy / resultMap feature.  This "grouping"  works in 2.1.7 but fails in 2.2 and 2.3 when it encounters a resultMap that contains 2 result elements that are themselves mapped to resultMaps.  We had written several stored procedure queries using the wonderful new multiple result set feature but had to roll back to 2.1.7 when regression testing failed on the complex nested queries.  There is no exception raised but the repeating property is not grouped for these elements.

Has anyone else encountered this?

I will post the query and result mapping if necessary but it is quite lengthy.