That was intentional. It seems to be valid tagging according to https://wiki.openstreetmap.org/wiki/Tag:highway%3Dtraffic_signals . Also the crossing for pedestrians and traffic_signal for cars are logically at the same place and when car has green signal, pedestrians have red so a car only passes the crossing once. It does not need to wait for green for cars and then again stop at another crossing because pedestrians have green too. That can happen when car turns, or when the crossing is at the other side of the intersection.