CDJ 2000 NXS2 Optical unit noise

I just bought a brand new pair of CDJ 2000 NXS2 a few days ago, and I notice this: when I power on the unit or insert/eject a CD a strange squeaking noise (like something is broken or not in the right place) is coming from the optical drive of the CDJ. The unit can play CDs without any problems!

I made a video about this: https://www.youtube.com/watch?v=qn18n49ycG8

The other unit makes no sound like that, as you can hear from the video.

Is that sound normal? It doesn't sound normal to me.

Should I send back the unit? I'm afraid that in a few years of usage it will definitely break down.