Improper driving practice i.e. "dropping" the clutch whilst engine is turning at extremely high revolutions.
Down changing of gears i.e. 5th gear to 2nd gear by a low speed/high driving gear method.
Wear on the stop pins indicates the clutch plate has been wound past specified torque loading. This has the same affect on the springs.
Misalignment.
SOLUTION
Driver education.
Refer misalignment tips.
Vehicle used for performance driving. It is advisable to use clutch disc with higher stopper torque capacity. Refer EXEDY Performance and Sports Clutch listings.
Not aligning clutch disc and forcing main drive into the spline, therefore, bending the clutch disc hub towards the engine as seen in photo.
Note: Hanging the gear box during installation pulls the clutch disc hub towards the gear box.
Driver resting foot on clutch pedal causing clutch slip due to clutch being in a semi disengaged position. This has caused extreme heat which has warped the disc.
SOLUTION
Do not hang gear box during clutch installation. Always use a clutch aligning tool.