How can I disable the system feedback when using the "fn" button on a Touch Bar-equipped MBP? I use Shush to auto-mute my microphone on voice and video calls, where I toggle my mic on by holding the fn key.  But on a Touch Bar equipped MBP, the system issues a click and pop noise when pressing and releasing the fn button, and it's driving me batty. 

How can I disable this feedback noise?  (And how did you figure this out?)

Update: I should note a few settings:


System Preferences > Sound > Sound Effects > Play user interface sound effects is OFF
System Preferences > Keyboard > Dictation is OFF
How embarrassing: the clicks were due to Shush's audio cues. I thought I had disabled them.