I say glitch on an early version of Kabal. looks too neat to be battle damage. The mask above his forehead is cut straight across and does not look to be "broken" at all.
I don't think that's how Kabal will look without his mask. I'm sure that there was a glitch or something of that nature. If you look at Kabal's HD VS pose renders, you'll clearly be able to see that he is horribly disfigured in the face as well.