ASUS DRW-24B1LT sounds of silence

I have two of these drives, both with 1.03 firmware. Both drives work flawlessly.

Assume both drives are open and contain no media, and are then closed.

The first drive makes the normal "sccchliickk" sound as it closes, and then is silent.
The second drive makes the normal "sccchliickk" sound as it closes, and then instead of being silent, makes an annoying bzzt bzzt tick sound.

These drives are on separate computers. Swapping the drives over makes no difference - one is silent, the other is annoyingly not so.

When booting, the second drive makes the bzzt bzzt tick sound twice, and the other is silent after a few quiet clicks.

Should I take the second drive back and get it swapped over now while I can, before the people I bought it from bully me into sending it back to the manufacturer?

Or is this weird sound just part and parcel of different batches?

Anyone else got the DRW-24B1LT 1.03 firmware and can describe the sound?