Something i noticed that the player cannot do is that enemies have both extremely accurate throwing skills, they rarely ever miss, and if they do miss slightly, it still hurts the place where the grenade lands, unlike the players where if they miss it miss everything.
I know you are aware of the later, though i'm not sure if you were aware of the former.
The same rules should govern grenade use by enemy or the player characters. I will say there are known issues with Grenade Launchers right now, but to my knowledge thrown grenades should be working. My guess is that the enemies probably won't throw unless they have a high percentage throw but we will check it out to make certain. We will also check on the damage on a missed grenade.
(FYI - I have definitely seen an enemy grenade miss)
