I updated my Sony A9ii to the newest firmware update (3.20) today and now every time I hit the shutter (when in silent mode) to take a photo there is a very strange zapping noise, sounds like a laser. The noise is specifically coming from the left side of the camera body where the headphone/mic jack, USB terminal etc are. If I put my ear to the side it is quite prominent. 

Camera was working perfectly fine yesterday before the update. Not sure what I can do or what my options are. I need my camera on silent mode for work everyday so I think I'm in trouble here.  Any help would be great. Thanks.

Did you try changing the (artificial) sound of the electronic shutter? Could be that.

https://helpguide.sony.net/ilc/1960/v1/en/contents/TP0002795822.html