As a standard practice, I sent you a bug today and I'll post the problem here. I'm doing this in case other players might see the same issue on other ships because I haven't had the chance to fight all the races yet ...
Bug : Kuntari Cruiser-3 ... one shot kill against it showing damage (orange text) with a 10-digit value.
I first encountered this bug in v337. I tested it a few times and my first impression was that it only happened when I shot the cruiser in the front arc. In my current saved game(338-30), I had more time to test it since the Kuntari is allied (I was at war with them in 337). I discovered the facing didn't matter nor did the type of weapon and damage. My second impression was that the tech level of the weapon might be overkilling the shot or perhaps the extra abilities, that was true for both cases in 337 and 338.
Bonus bug ... After you kill the cruiser, hit space bar and finish the round. When the next turn comes up, goto the races screen and note the Kuntari relation hasn't changed. I think they should be a little pissed, huh?

EDIT : I have a screen shot (using F12 hotkey, Steam) ...

Thanks!