No.
For the past 2 weeks, I have been using my cell phone for making calls and avoiding using my desktop for making calls (through google voice). As a result, I haven't been switching the default audio unit from 1 to 5 (in my case). I used my desktop today and after switching from 1 to 5 for the default audio unit, the buzzing came back in the USB headset. Oddly enough though, after finishing my call and reverting to 1 for the default audio unit, the buzzing hasn't reappeared.
I am baffled by this.