Parallel query plan returns different results every time that you run the query (4 CPUs - SQL 2008R2)

I'm experiencing the problem where a parallel query plan is returning incorrect results on a multicore processor system.

The problem is described in http://support.microsoft.com/kb/981502. Having tried the workaround, setting OPTION (MAXDOP 1), it fixed the issue and also confirms that this is my problem.

I would like to apply a permanent system wide fix, so I patched the sql server to version 10.50.4290 using CU8. 

My query does not contain the row_number function so it is not related to the problem described inhttp://support.microsoft.com/kb/970198

I have enabled the trace flag 4134, by issuing the command DBCC TRACEON(4134,-1) in the stored proceedure experiencing the issue.

However, the issue still persists and I would appreciate any help on this matter.

Carl Stent

References:

https://connect.microsoft.com/SQLServer/feedback/details/642790/parallel-query-plan-returns-different-results-every-time-that-you-run-the-query-8-cpus-sql-2005-2008-2008r2

http://social.technet.microsoft.com/Forums/sqlserver/en-US/7c01779c-ee05-4f6d-8e1a-2bf2fa017f0f/parallel-query-plan-returns-different-results-every-time-that-you-run-the-query-8-cpus-sql?forum=transactsql

http://support.microsoft.com/kb/2727322/en-gb

http://support.microsoft.com/kb/981502