Given the right circumstances, the SSIS OLE DB Source component in the Data Flow will return no records at all, although it should actually return records.
The bug occurs when the OLE DB Source uses at least one parameter and has a comment line right above the WHERE clause. The comment should be one using a double-dash. In short, this results in FMTONLY being set to ON while running the query and thus results in zero records.
More details: http://blog.hoegaerden.be/2012/12/05/ssis-ole-db-source-parameters-and-comments-a-dangerous-mix/
I should also mention that this bug no longer occurs in SQL Server 2012.