All gates are not created equal. The flow from some gates is blocked by the shape of the casting in front of them. In the attached example the center gate was effectively blocked by a step in the part shape in front of it. The simulation appears to allow metal to enter the part through the center gate. A short shot demonstrated that this was not true. The process was fixed by a tuning of the casting shape

Gates are effective when 50 mm of straight air path exist in front of them. #Soldering and #erosion occur when this is not true.