I believe this is called hill start assist in many vehicles, not sure what Mazda calls it. The vehicle keeps brake pressure for a second or so to keep the car from rolling back while getting your foot from the brake pedal to the gas pedal. This comes standard in many vehicles nowadays.
I haven't yet run into this issue as there are not that many steep hill in my area ut the information you provided is helpful.
I haven't yet run into this issue as there are not that many steep hill in my area ut the information you provided is helpful.