Also, this is the case with my Bryston BDA-3 and OPPO Sonica DAC, both can do DSD native, but Roon 1.3 does not see them as native DSD and have to select DOP.
Also, I have an iFi Nano DSD and that works fine, roon sees it as a native DSD device and I can select DSD.
I am using a RPi 3 with the latest DietPi 1.43 image, both DACs are connected USB. Roon Core on a ReadyNAS_516, Linux RPiAllo 4.4.44-v7+ #2 SMP Wed Jan 25 23:12:28 UTC 2017 armv7l GNU/Linux
Thanks