I used a 4s on a 3s 2212 motor with a 4s rated esc.. after a few stress-tests, it started burning. When the fire was off, I tried to spin the motor manually, but it was really hard to spin. I think, that the higher rpm destroyed the bearing and due to the higher resistance, the amps raised, so it fried because I didn't use fuses. Btw. there was no prop attached to the motor.
I hope, I could help you