At the spot in the swamp where you find the note, I found the note, but couldn't pick it up. I could read it, send it to camp, but couldn't send it to any player character or pick it up with any player character. Not even from the chest in camp it got sent to, or after loading again, could I pick up the note. Also, reading the note didn't impact my characters or quests at all. Might be because I read the note after defeating the goblins with Halsin, so he was at the Grove at the time I found the note, but I assume it is more likely part of the bug preventing me from picking it up.