Ok, so I'm pretty sure this is a bug. I've seen it once or twice before, and both times I just wrote it off as not understanding what I was seeing, but now I want to report it just to be sure.
I'm playing against the AI, they have the ball. I make one of my beastmen get up off the ground and try to blits the human with the ball.
The game lets me go after him. My beastman successfully pushes to reach him then POW! no blockdice are rolled, the guy just slugs my beastman.
It look like the animation that plays when you attack someone, but roll a skull. Only the attack dice were never rolled. The game just seemed to decide. "NOPE, you ain't hitting me." And dropped my player like a bad habit..