Its the bathroom my GF uses so I can’t answer the question about shitting. Also I have no idea what they did/didn’t do because she was the only one home and she just gets annoyed when I ask because she thinks I worry about house stuff too much (I do). I don’t think it’s a leak at the tank. I could see there actually being some kind of crack somewhere on the inside. Somehow the water from the tank has to move to the front of the bowl which is where the new water comes out when it’s flushed. From what I can see there’s no water anywhere except the front part of the base, like where your feet would be when sitting down.