Ironically my Frigidaire front load washer did the same. For a low budget machine it works well and has an on board heater. Mine too did the same thing for prewash. Used cold tap water and then heated it up.

My Miele with cold and after a few minutes turns the heater on. I think stains like blood remove better if cold water is applied to them, so perhaps that is why these machines are starting with cold. I think this is the best way for a prewash to start, that way a variety of stains and dirt can get a pretreatment.