I'm experiencing this exact same harsh, painfully loud glitchy sound that happens randomly yet frequently between ads and songs. It's maybe once every 8-10 transitions between songs/commercials. The OP was right on; it sounds like someone yanking the audio cable out of an amp with the power still on.
Besides the fact I look like a total spaz when it makes me jump and flinch violently at my desk, it really, really freaking hurts if you happen to be wearing headphones! I listen to music at a low enough volume and with open-style headphones so I can hear a bit of the outside world if I need to, but this sound is insanely loud even at a low volume.
My temporary solution is just to slide my headphones off my ears during commercial breaks. Not only do I avoid the random, ear-stabbingly loud glitchy sound, but if I listen to one more febreze commercial I might actually go totally mental.