I have this noise when I start moving, as the clutch engages but I also hear it if I let off the gas or back on in low gears. I have the cpe2 rmm and had checked its tight. On Facebook people said its clutch chatter but I also hear it with clutch fully engaged, moving in 2nd gear for example.
Sure sounds like an under torqued rear motor mount. Verify torque on all fasteners and use loctite. If the fasteners get looser you'll be able to replicate the sound consistently by getting on and off the throttle as the engine rocks. The vertical subframe fastener may already be marring the aluminum RMM hole.
The torque on all fasteners was checked, also tried to reproduce the sound by having the car on a lift, keeping the foot on the brake while slowly engaging the clutch and could not reproduce.
OP, any recent work done on the back end of the engine? I had a similar clicking noise after my HG recall was done which turned out to be a loose head shield.