I don’t have PCOS, but I do have hypothyroidism. When I went from a desk job in an office that I’d had for a year and back to teaching where I’m on my feet the majority of the day, I lost 15 pounds without changing anything about the way I eat or anything else I do.
I would say if the weight loss concerns you, or if it doesn’t concern you now, but continues further without you doing anything additional beyond your new job, then check in with your doctor.