Has anyone had any further ideas about the 'other' bug in the Hatari Falcon audio emulation?
Around 50% of the time the crossbar/codec is initialized, there is a loss of sync between the codec buffer and the host audio buffer, resulting in crunchy distorted audio. From time to time the result is really, really bad.
As Laurent pointed out, opening the Hatari sound menu and switching the audio quality down (e.g. to 11khz) can often 'fix' the problem while the audio is playing. It's then possible to switch back up again to 50khz or whatever and get correct sound. It sounds like a desynchronized ringbuffer, or wrongly sized buffer - samples being dropped from the output at regular intervals.
This trick with the menu doesn't always work - sometimes it takes 4 or 5 attempts. Sometimes the sound corruption changes a bit, improves or gets worse.