Well, it could cause an abnormal bend when fighting a fish and potentially break the rod. But I have a few cheap casting rods that are slightly curved on the last 1/4th of the rod, they have not broken yet. I use them for catfishing throwing 3-4oz weights and fighting fish in the current.
I would just chalk it up to foreign rods, I’ve only seen it on china and mexico made rods. I try to buy rods made in USA now, seems they are always top notch quality and only a few bucks more than the chinese crap.