Another LBS who had a very good reputation for wheels, I had two wheels built by one LBS, one lost six spokes in one go just like that picture (but on the front!), the second wheel lost 3 at once, and then after that I was losing one per ride.
So eventually I took both wheels to another LBS, who rebuilt them with the same type of spokes, and nipples on the same rims/hubs and the problem went way. I was told to ask the original LBS what tension they checked them too with their spoke guage, and when I asked, they said they didn’t bother with spoke tension gauges as they checked them by eye/hand.