Soundcard FM Distortion

My focusrite Saffire USB soundcard is a little temperamental at times, especially when I wake the laptop up from sleep mode.

Anyway, I loaded fairly standard bass guitar patch into Ableton and played a note on my bass, and what came out of the speakers was the most awesome FM sounding distortion, like a Yamaha TX/DX almost but via a live bass guitar. I wish I'd recorded a sample to be honest.

Could anyone shed any light on what could have caused it, and how could I replicate it, if possible? The audio input was clipping in the red but not at the top of the volume bar, so some very squashed signal maybe? Possibly a buffer thing? Fuck knows but it sounded awesome.

Yeah my guess is a buffer thing too - either an underrun (not quite enough shit in time) or overrun (too much shit in time)!