Don't quote me on this, but I think drivers are allowed to drive on a flashing yellow light without coming to a full stop, while this red light requires drivers to come to a stop.
Flashing yellow means yield, indeed. However, if the traffic lights are off the signs take precedence which in this case also just say yield. The red light with the green arrow is a hack in that it allows the intersection to work as intended, but the Stop part of it probably is not strictly necessary here.