You are correct.
If there is any condensation in the engine (which they all have) and you start it for a short period of time the water will mix with the oil. It may separate at first, but Starting over and over again it will eventually turn into a milk shake color. Then you get to do another oil change.
If you run the engine till the engine gets hot the water will evaporate. You would want to do this every time you start it.
All engines are designed this way.