I noted the Druid Grove had become aggro when I approached the front gate after I had saved Sazza the goblin by guiding her through the underground passage. My first assumption was that it was because I had rescued her, but not so.
I backed through several saves to one where I had cleared the passage but had not freed her. I chose to leave her in the cage and when I left the jail area going back into the grove, I got a narrator dialogue indicating that "my attempt to disarm the trap has not gone unnoticed" and the Grove was aggro.
Haven't yet determined if it's because I disarmed the guardians in the underground cave or the poison gas in the room adjacent to Netty's area.
I'm classifying it as a bug since when you approach the front gate, you don't get the narrator dialogue giving you a clue as to why the teiflings are now raining down arrows, only if you are going back in near the jail.
