About every 2000 hours or so, the dreaded " Genesis Flapper Fiasco" occurs. Usually during a busy day or week. About 1-2 hours to repair, if you have the spare parts. I had one. Oh, and you have to let it cool down for an hour or so before even touching.
That happened to mine early on, it had the electric solenoid actuator. That one slammed open and close. 2700 hrs on the current one with the vacuum actuator, it closes nice and easy.
True. 304 stainless is your run of the mill variety, and what you find most often. 321 has much better resistance to fatigue and cracking at elevated temperatures.