Get some one else to engage & disengage the blades while you watch the clutch from the rear ( remember eye protection ).
A lot of clutches have a bit too much play between the housing and the anchor pin / plate which can sound like a click or rattle.
If it sounds more like the deck then have a close look at the spring on the tensioning arm.
If things look loose then as suggested above send an email to the dealer you bought it from, and KEEP A COPY.
This can be important latter is a warranty claim needs to be substantiated.
When returning to the dealer with the complaint don't be surprised if the first words from them has something to do with the possibility of operator error. That must have been a prominent subject in dealer/salesman school because it's sure used frequently.
I'm going to try to get a vid of it to post tomorrow. I'm 50\50 if it's a real problem or just the sound of the belts running. They are heavy duty. Coming from old Craftsman rider - it was just a rhythmic drone when the blades were engaged. This is a whole different machine.
