It's a known fact that the trans will make a noise under deceleration with a lightened flywheel. I have been down this road on my own car every since I swapped everything. I did everything from swapping transmissions to a couple different aftermarket clutches and flywheels. Out of three different transmissions the only time it went away was when I put a stock flywheel back in. I did however get completely lucky when my spec clutch finally went with my stock resurfaced flywheel I bought an act 6 puck and a street light flywheel (first flywheel I noticed the noise) and now it's totally quiet.
Chances are if you just had your stuff done and running a lighter then stock flywheel this noise is because of that. If you've had this set up for a while with no issues before and it sounds like Aarons vid then you probably have an issue.