have the dealer try the bulletin repair again, this time ask them to use loctite threadlocker, might work for your situation or at least a while longer

 

FYI: There is a ongoing issue with a loud rattle/vibration coming from the rear deck of recent version Accord sedans. I took mine to the dealer (under warranty) and they fixed it with some felt padding of some sort (so they said) Good Luck.

 

Refer to the link address in post #2 of this thread if you want to see the technical service bulletin fix.

 

Unfortunately the standard fix for the rear deck rattle isn't working for me. The rattle I experience comes and goes therefore it's really hard to locate exactly where it's coming from. I've had my car in 4 times for this problem. I'm at the point now where I'm just dealing with it and turning the radio up when it starts.

 

Add to the list of various rattles throughout my Accord: something in the steering column, possibly the ignition. The small speaker located on the driver side door by the side mirror. The passenger side visor. The inside moon roof slider screen. And of course I can't forget the rear sub woofer.
I must say this is the most disappointing car I have ever owned. If it was a $10,000 Kia I wouldn't mind as much. But the sticker on a 2012 Accord EX-L V6 is slightly higher than $10,000. Very disappointing.