Try creating a new ProgramID instead of reusing your present one. Past versions of NW has issues with latency where the ProgID was concerned. Not sure whether 14.0 has the same issue, but since it is not related to the MII version, I would not be surprised to see the same problem crop up. This is a long standing situation where the Program ID is concerned. Never ever reuse them. Always start from scratch just to be safe.
The best way to test is to create a new one IDoc Listener with a new ProgramID. I would recommend for testing that you make up a ProgID that is named something you would not use normally. Something like XYZIDocTest0 would work fine. Once testing is complete, you can then recreate another new Listener with proper naming.
Regards, Mike
SAP Customer Experience Group - CEG