Game Froze on Manticore Mission

I’m playing in insane ironman and my game froze when I got to the Golden Manticore mission in the first chapter. Got to the last point I needed to win when the last wave of enemies spawn in. There was an e-hole which I put a grenade over so when I ended my turn and the grenade detonated the game freezes right there at the end. Any suggestions anyone ? I’m on steam BTW