I am certainly no expert, and have only been keeping ducks for 2 years. But this sounds normal to me. Lots of my ducks like sleeping in their water tubs (and their pool!).
I did have runner ducks for a brief period. I found they liked splashing and playing in water as much as any other breed. I don't really think there is any breed of duck that'll be disinterested in swimming or playing in water. From my own research, some breeds require a pond/pool for breeding and others do not, but that's really the only major difference - at least for mallard-derived breeds. They are all still waterfowl after all!