Tinking, Sparking noise. Please help.

Hi guys,

I have a 2013 Volt and having an issue that I need your help.
Please watch youtube that I have posted (volume up). Can you hear clinking, tinking, sparking noise? It is difficult to describe that noise.

My Volt makes that noise in random time; however, it is not hard to replicate because it always makes that noise. I said random because it makes that noise sometimes when I hit the brake, release the brake, or even idling. But it always does that when it is slowly moving and stop. However, it doesn't do that when reversing.

I took it to a dealership for an inspection. The service advisor said that it is normal sound which every Volt makes, and further he said some volts make that noise when it is new and, for some, later. This explanation just doesn’t make sense to me. Is it to you guys? Furthermore, the type of noise that I am hearing wasn’t normal. Is it to you guys? To believe him, I asked him to bring a Volt which makes this noise from their inventory then I will believe him. He said no. Also, the technician ran DTC and there was no error code, and he visually inspected the vehicle and did not see anything wrong.

My questions to you guys are:
1. Is your Volt make this noise? If the noise is normal, then there must be many of your Volt on here make that noise.
2. Has anyone had this issue and got it resolved?
3. Those of who have not heard this noise before, is this sound normal robotic sound to you?