I’m having a very similar problem:
– Raspberry Pi 2 Model B
– Fresh M2P install with JiveLite
– Sound output via HDMI
– LMS running on a different machine, no problems with any of the other clients
– I’m NOT using synced playback.
With this setup, I have sound dropouts as described by hanszorn. The M2P machine has a filesystem expanded to 8GB and CPU load is typically below 5%. HW codecs are activated (which should not make a difference 😉 ). When I take the headphone jack, the dropouts do NOT occur. Well, waiting for my HifiBerry DAC+ and hoping, that there will neither be any dropouts.
Nevertheless, it would be nice if you could assist in solving this issue.