Just captured this from my 5X.
So looks like the new build is not NRD91N but N5D91L.
Google has uploaded build N5D91L factory image and full OTA.
Factory image: https://dl.google.com/dl/android/aosp/bullhead-n5d91l-factory-7151a923.zip
Full OTA: https://dl.google.com/dl/android/aosp/bullhead-ota-n5d91l-b2644ba5.zip
yeah, I noticed that, too. I just flashed it and it runs stable as expected. does anyone know the differences between NRD91N and N5D91L as I didn't find anything in the web?