5.1 audio playback glitch on first start

On cyanogenmod (cm-12.1-20150822-NIGHTLY-m8), but this problem has been occurring since 12.0. Any time I start new audio either using the default 'Music' or Google 'Play Music' audio players, there is a very loud audio pop before the music starts. When this occurs with headphones, its far too loud and could easily lead to audio loss. Seems to only occur on the first playback attempt.

Video below demonstrating the default CM12.1 audio player -- but can also be reproed with Google Play Music, thus a OS problem: https://www.youtube.com/watch?v=CTXcKklggeY