The last nightly that worked properly was KodiSetup-20170425-8056f3533b-master.
From 20170427-8f8ff1ef4b-master to 20170428-5e12c6146f-master I have experienced persistent but randomly timed audio dropouts of random length. They occur roughly every 20-40 seconds and can last from 2-30 seconds.
Using WASAPI with the 5.1 CMedia USB DAC is noticeably worse than when using DirectSound but either way the problem persists.
I tried changing audio resolution, bitrates, etc. but nothing changed and the issue persisted.
Once I rolled back to 20170425-8056f3533b-master by installing over the newer nightlies, the problem resolved.
I opened BugTrac ticket #17453 to report the issue.