Annoying buzzing sound that sometimes plays in act 3

Hello. Lately an annoying, continuous buzzing sound has started to occassionally play in certain areas in act 3. (So far in my experience Marketplace, the City of Sarn and Warehouse Sewers). It's never happened until lately. I'm sorry I can't provide much detail. It's a continuous buzzing noise that suddenly starts to play in the background.

This is happening to me right now. So I am reviving this thread with no answers.