Dumb questions so I apologize - I assume you entered your grist, lovibonds, and volumes into Brunwater correctly? Weighed out salts correctly? Also, I learned a new lesson on Brunwater this week that I should've figured out by now- that it's more accurate if you subtract your boiloff rate from your sparge volume in the software. What is your boiloff rate? Martin said that higher boiloff rates will concentrate the water additions, which seems obvious but wasn't to me. Concentrated additions could = undesireable results. Also, I'm surprised that Carafa III @ 3.8% would ever come off as acrid and unpleasant, having so little roast. The last stout I brewed had almost 11% of combined chocolate and roasted barley and was like chocolatey espresso. What profile did you go with - black balanced ? Just wondering.
Edited for grammar and dumbassery.