Kerning Fire Hydrants

This is really bizarre. Whenever there's a fire hydrant in my regular attack's swing arc, any monster inside it acts as if they weren't hit at all. Skills work normally however. My guess as to what's going on is that the fire hydrants are reactors. They don't do anything when I attack them, but then again it could be like Witch Grass in Kerning Swamp where they don't react if you hit them on the wrong side. Except... the hydrants do nothing either way.

Are the fire hydrants part of some new quest or something? Or should this really go into MapleBugs?