An "optimization" change made a couple years ago severly hurt gralat spawn rates in inside areas. It was probably unintentional, what it did was make players/npcs only load if they're in view in inside areas(previously on non gmap single levels it did it for the whole level), so if your afking in the water at the fan you no longer are helping others farm. it literally went from making like 15-20k an hour to 2-3k an hour since you need to be near the spawn location for it to help the rates.