I have no idea if other airlines have had incidents or not.

I think the meals are either boarded in casserole / aluminum foil dishes with aluminum foil covering them.

In addition, IIRC, not all of the aircraft have specific bread warmers, so there is generally no room to warm bread when casseroles are taking up all of the oven space. I have no idea what the policy is but perhaps the bread is allowed to be warmed on aircraft with bread warmers.