Hi,
I just finished my Odroid C2 Project and I want to say thank you very much to all who made this possible.
How does my system look? Well, I wanted to use Bubble Upnp/DLNA on my android tablet as control point. As local upnp server I’m using MinimServer running on my Windows 10 file server. I’m also streaming songs from Tidal (HiFi mode). My local radio stations are shoutcast streams also controlled by Bubble Upnp. I’m using an older USB DAC from DIYINHK at the moment and feed the output into my Denon AV receiver. On my Odroid C2 I’m using a modified Volumio2. I replaced the frontend and the backend because I had problems with clicks and pops in the audio output. I first changed the frontend to the openhome MediaPlayer but the clicks and pops were still there. Then I replaced the backend (mpd) with mplayer and the pops and clicks were gone. Also the support for shoutcast streams is now working perfect. The default software on volumio2 has some restrictions with the playback of shoutcast. With this configuration I do not need to use the volumio2 web interface. Everything is done with Bubble Upnp. I’m totally happy with this setup now. 
So in your case, mpd caused the clicks and pops? Very interesting find…