Air Play

Hmm. I’m guessing that is a function of your Aurender 200. I have used airplay on other devices and it has been simply terrible... unreliable, poor quality... etc. 

I’m just going to have to take a guess that the Aurender is caching the contents and then re-streaming them... basically reconstructing the bit stream then sending it off to the DAC. On the devices I have used Airplay... like a Tivoli stereo, Apple Home Pod, etc... the incoming bits were simply converted to audio... and the sound was terrible. Interrupted and bad. 

I think you’re right.  The Aurender is doing it.  
Amazing device!

AirPlay is quite good on my Cambridge Audio CXN 100.  I rate it as just a notch below CD.  Chromecast is better still but you need an Android device.

They both sound much better than Bluetooth