Hope this isn't against any rules, and the forum members who own this product don't take offense. I'm not speaking of a poor purchase. This is a design flaw, cut and dry. To use metal that will warp due to heat, on one end of a fire pot is preposterous. That's about as silly as making a wood-burning oven from fender material.
If more thought was put into the product, it would be a thicker part. In retrospect, the vendor might consider replacing all of them free of charge. It wouldn't be impossible to take a thicker piece of steel, and mill the ends out thinner to fit the existing slot dimensions.
I'm truly not trying to stir the pot here, but if this offends, moderators please accept my apologies and delete this.