Hiya
I know this has been mentioned in some of the other release threads, but I thought I would put one in the bugs forum as well, so other people experiencing the bug can find it easily.
I had a Caesan who I could not auto-target, and did not get injured by an alenium grenade at his feet.
I did manage to get a crosshair to show up on him at one point, but my mouse pointer was not over his square.
I tried hitting him with a stun baton (by clicking the UI pic and hitting the square) to no effect.
One of my guys reaction fired at him, and I got the "miss" pop up.
Finally I tried throwing a stun grenade, and it worked! I lost two guys to him, but got him in the end.
I don't know if it would have made any difference, but the stun grenade was thrown the turn after the reaction fire.