Well, it’s noy so strange, it sound only strange becaus they show only one of the multiples telemetries of the ISS. The amount of Urine is only one of a huge amount of different datas, to control the resources of the station in a circular system of water. The amount of water from earth is limited and not enough for an team for several month, if they don’t recycle the waste water and also the urine. Because of this is needed to know the exact amount of it. Even so, after some month in the ISS, they describe the smell as one of an puma cage.