The team is aware there is an issue regarding some players not receiving their achievements after completing the game in Honor Mode.
While the team is investigating the cause of this, we have found a workaround that should allow you to receive your achievements:
- Go into appdata and rename the baldursgate folder in local. This will make it create a new folder on startup; treating the game as the first time it launched.
- Move over the save from your other campaign and finish the game. You should then get the achievement.