Sorry for your inconvenience.
But this case you already discuss with your Japanese boss yet?
The last time (30 Sep'13) Anzai-san reply e-mail to Araki-san that this problem may be came from manufacturing process.
And ask Matsui-san to check and investigation.
I'm afraid this problem may be same as previous.
Because you found noise after assy with other part, right?
How about incoming inspection result?