Good evening everyone
After getting all the other achievements I finally turned my attention to this achievement , after hours of grinding out clinics and placing endless lighthouse paintings I finally got to 100 happiness in my sanctuary settlement yet this achievement has failed to drop. I have tried sleeping for 24,48 and 72 hours. I have tried leaving sanctuary and returning. I have even tried scrapping and rebuilding the clinics. Yet nothing will work in getting this achievement to drop. I really hope this can be fixed as I really cannot be bothered grinding out another 10+ hours trying to get this to work on another settlement.