Increased delay when AUGraph's output device is system output

I'm using an AUGraph to mix audio from different sources for a real time streaming application.

Whenever the audio device used as the graph's output device is also the Mac's default output device, the measured latency increases by about 35 milliseconds for wired devices.

Any idea why this is?

Is there a way around this besides nagging the user to not the use the system output in our app?

Increased delay when AUGraph's output device is system output
 
 
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