This is true for a lot of mechanical devices. For example, turning engines on and off heavily thermally cycles them. It can get worse when they are rapidly coo

This is true for a lot of mechanical devices. For example, turning engines on and off heavily thermally cycles them. It can get worse when they are rapidly cooled or rapidly heated. Jet engines running at constant speed have high cycle fatigue to worry about, but steady temperatures don't pose a thermal stress issue. But shutting the engine off in cold air and letting them go from very hot to very cold suddenly will cause the thicker parts to cool slower than the thin parts, stressing them near the change in thickness. That results in low cycle fatigue (where you can count the cycles to failure in the dozens/hundreds/thousands vs. millions/billions for high cycle fatigue).