it is hard for me to comment since my bully has digestion conditions anyway, so this can be normal for us. Did you change her food slowly? How long has it been since the switch? I would monitor it for a little bit and see if the condition changes, also beware of what treats you are giving, those make a statement too. Are they also grain free? Any people food snacks? You will have to evaluate all that goes into the stomach.
Keep us posted, please I am the diahrrea paranoid momma on here. My Bella was born with a congenital digestive issue and anytime Poo isn't right, I worry.