I have tried using the Phoenix Point grenade launcher, the Goliath GL-2, around 10 times now and I think roughly 50% of the times, the targets the game UI showed me I would hit wasn’t hit at all when I fired it.
The problem is that even though it clearly shows me that I’ll hit 2 crabmen, it doesn’t take into account that there’s actually a roof over them that the grenade will hit pretty much ½ the time.
I’ve had similar problems in other fights, but for this one I decided to save just before the shot so I could try it out a few times, and it seems to be pretty common sadly.