I'm getting some weird behavior when trying to synthesize a hi-hat-type sound using mc.rect~ with FM and Pulse Width Modulation. It sounds ok at first but then quickly sputters out into some weirdness that I can't figure out. This mostly happens when pushing the FM index past 1. If I reinstantiate the mc.rect~ object in the patch, it sounds ok again for a while but then goes back to sounding somewhat like a CPU overload or something like that.