What is wrong with this soldering iron?
The tip is not mounted correctly on the iron body!

It is absolutely normal that a soldering iron becomes brownish due to oxidation around the heating element - which for such tips should be inside the sleeve. But it is outside! The iron also looks "unnaturally" long.

When zooming in and looking into the slit, the iron body is not inserted completely into the sleeve, it does not even reach the small clamp. One can see the background and the shadow of the clamp on the backside. 

If  the iron body would be inserted completely, the heating element indicated by the brownish discoloration would be inside the sleeve as it should, and the iron had a more "natural" length.

Using the iron as it is could definitely cause it to bend, because it puts much mechanical stress on the body, which becomes weak under the heat. And the heat does not reach the tip well, and doesn't melt the solder well. People tend to push more then, which finally bends the iron.