maybe i'm looking at this from the wrong perspective, but i have seen the clutches on the bikes our students use for learning to ride a motorcycle, over a 2-day course the bike has spent most of its time in the friction zone, day in, day out. When you take them apart when they have finally failed, typically after a year or two, depending on the bike, sometimes longer, they show wear, and burning, steels turn dark tan and black, but not a burnt black, if that makes any sense. Before anyone loses it, I know it isn't a rocket, but this is after a period of much longer than 2-months, with mid to high RPM while riding the clutch for incredibly longer periods of time than you would on the street, they would be exposed to a long term accumulative effect.
When you look at the pictures for this persons clutch, you see oil in the casing as you would expect, and you see the deposits of metal and what appears to be burnt fibres, also when you look at the fibres and steels, some of the fibres look like they are almost charred, but definitely they have been burned, some of them you see oil on them, some you don't (possibly due to being wiped off during removal) and some of the steels are black right down to the teeth, that whole clutch pack looks like it took on a lot of heat. I'm wondering if there might have been an oil flow issue in the engine, where the clutch for whatever reason just wasn't getting the level of oil it needed, just a thought,