I had one Chinese who molted way too low to the ground so he bent his back. He never did start eating again (lack of desire) and died. I've heard it can be debilitating.
Such serious deformities are very likely to cause death. Bent organs may cause blockages or other problems but it's purely speculative. What I'm sure of is since the thorax is the starting point of a molt, a bent one will almost always cause a mantis to die.
I currently have a D. lobata male that got a bit stuck in a molt, so he has a bent thorax and a bit mangled raptors. But his four back legs work fine and he has a good appetite when I hand feed him. I'm waiting to find out if his next molt can fix anything, or if it's even a successful molt. Depending on how severe the mismolt is, sometime they can't recover.