I think you have a defect if the jack bent just because a wheel came off the ground. The jack should have been more than ample to carry the load - sounds to me like Coachman short-changed you on jack capacity.
With an automatic system you don't know when a wheel is going to lift off until it happens. Besides, it should be strong enough anyway!
I'm not recommending lifting wheels off the ground, but the system ought to be strong enough to handle it if it happens.
Former owner of 2004 American Tradition and several other RVs
Home is in the Ocala Nat'l Forest near Ocala, FL
Summers in Black Mountain, NC