I had a verified genuine carbon fiber seat post assplode on my MTB. It was also verified to not be due to crush forces. It just plain sheared off.
I have also had an aluminum handlebar fail due to metal fatigue.
And, the chain stays on a steel frame fail due to metal fatigue.
Oh, and a head tube get bashed out of round on a steel frame HT MTB.
Is it maybe being 240 pounds?