This roof leaked the first time it rained after the buyer purchased his new house and likely leaked on the architect’s drawing board. Architects these days actually use computers to do their drawings. Likely there was a wet spot under the monitor.
The buyers figured they did not need an inspection because the house was new- after all the town inspector passed it.
This is not the way to configure a valley. The water streamed down the wall and into the basement. He ordered a complete inspection the day after the rainstorm and we found a number of other significant defects.