macbook pro 13" left speaker buzzing

I bought my very first MacBook Pro 13" ever on 02/14/18. When using it I noticed that there was a buzzing noise coming from the left speaker. It's not loud but in quiet areas, I can notice it. It doesn't do it all the time. When it does happen I could have 1 app opened, no apps open, or a bunch of apps open and it happens. The buzzing noise doesn't seem to affect performance, but since this is my first Mac I wanted to be sure this isn't normal.

I called Apple support on 03/10/18 and they had me do a bunch of stuff to try to resolve it which it didn't. Then we scheduled a Genius Bar appointment for 03/11/18. Before my appointment, I decided to restore it to factory to see if the buzzing noise was due to my profile or whatever, but it happened then too. At my Genius Bar appointment, the conclusion was to send it out for repair. So we did and the top case with battery ANSI was replaced. Got it back and started using it and the buzzing was still there. I kept using the Macbook for a while like this since I needed it then.

I chatted with Apple support on 03/29/18 to discuss next steps which were another Genius Bar appointment for 04/06/18. At this appointment, they suggested another repair. At the time, I wasn't able to be without my MacBook for the number of days that the repair would need, so I held off until just recently. On 05/14/18 I had an appointment with the Genius Bar to send my MacBook in for repair. This time they replaced the top case with battery ANSI again and the logic board 3.5gb 16gb 256gb. Got it back and started using it and the buzzing was still there.

Am I just being picky since this is my first Mac or is there a real issue? I haven't talked to support since getting my Mac back.