Hyundai Tucson 2016: How do l stop the car from rolling back?

I’m guessing the transmission your transmission is a dual-clutch unit, which although it’s called an automatic it’s really like a self-shifting manual gearbox. If you can imagine you’re driving a manual and you take off, there’s a moment before the clutch takes up that the car is free to roll forward or back. That’s in effect is what is happening in your Tucson. There should be a hillhold function to stop the vehicle rolling back and the time this function holds the car before releasing can be adjusted. Check your owner’s manual to see how it can be set to stay on a little longer.