Buy American !!

I had a "good brand" (don't remember which one) twist drill bit catch on the edge of the hole I was drilling, and instead of just stalling the drill, it untwisted the twist. It looked like a drill with straight fluting down the length. Wish I would have saved it or at least a picture.

In your case, it looks like a soft metal was used and no heat treating done on it. I doubt that you got the bit so hot it lost its temper that far up the bit.

Steve