Are you sure it\'s a physical crack in the sensor? Did you inspect it under magnification or attempt to brush it away with a sensor brush?
If it is a crack, I doubt it would have been caused by the temperature variation. It would\'ve been due to mechanical stress or shock.
I should add, though, that such a crack could have happened because the sensor assembled or mounted correctly in the body. When the manufacturer mounts the sensor, they adjust it to be perpendicular to the optical axis. Incorrect adjustment could be the cause of this problem, and the temperature change could have induced it to crack.
