Around this time of the year, all reptiles are starting to eating less and sleeping more. My snakes including my bp is still eating (>500g) for now but I won't be surprised if he starts turning down meals soon. My king is showing less interest in food and being less active. She has been like this pre-shedding. I am hoping she will want to eat after her shed but as an adult female of unknown age, I don't mind if she cuts back as long as her weight remain about the same. My lizards are already showing less interest in their food or eating less, including my food obsessed blue tongue skink.
I think age plays a factor but even the young ones will follow suit if they feel winter is coming. I would not worry about your snake not eating for several weeks. Try once every 2 weeks. As long as the weight is not lost by much and they appear in good health, these guys know what they are doing.