@laemeur It was like that before, but the StatusNet documentation explicitly said it wouldn't implement "auto-connect-to-group" notifications for replies to group-related notices. So I treated it as a bug and fixed it.
However, there's a feature that I noticed while digging through that sends Salmon pings to other profiles (including groups) than the one directly mentioned. I haven't really understood how it's supposed to be used, but something is there to let the previous notice's mentioned profiles know that some third party has replied to it.
But it obviously doesn't work as it should.