Comment 12 for bug 1319233

This does indeed look PulseAudio-related. I'm able to reproduce with the default settings, which outputs to PA, but when I select the ALSA output module and a proper (hardware) device everything is fine.

It seems to me that there's a buffer issue, especially because of these lines:
[0x195d948] main audio output warning: playback way too early (-398592): playing silence
[0x195d948] main audio output debug: inserting 19132 zeroes