maybe it picked the cheapest node quite often. you might still get 85%-95% optimal paths - roughly heading the right way with occasional strange sidesteps and z

maybe it picked the cheapest node quite often. you might still get 85%-95% optimal paths - roughly heading the right way with occasional strange sidesteps and zigzags in the route if it was completely broken it probably wouldn't have shipped that way, so the defect meant it was probably only somewhat broken and the end result was workable.