[mirwa]

Of the top of my head, I cannot remember if fasteners through the bridge are a factory fit on these.

Either way, If tightening the fasteners down further removed the buzzing from your guitar, then I suggest you take it to a luthier and have the bridge removed and refitted or do it yourself.

Tightening fasteners is simply masking the bigger issue IMO, a non bonded bridge.

The only other thing I can think of, is maybe the fasteners had a washer fitted, and the fretting of the strings was causing a sympathetic vibration from the washer.

Steve