It's really hard to tell what could be the problem with all the data type manipulation being done in the query.

My first thought is that it doesn't have anything to do with the query but that there is a Filter in one of the objects in the report (dataset, tablix or data region) that is limiting the results returned. So I'd look for those first.

I'd also, in development, run Profiler to verify that what I think is being passed to the SQL Server is really what is being passed to the SQL Server.