Side/window Air Bag problems of the 2012 Kia Motor Forte

On 12/20/16, my oldest daughter was following my youngest daughter to have breakfast. My oldest daughter drives a 2012 kia Forte. My youngest daughter was at a red light with my kia-driving daughter directly behind. The light turned green, and for some reason the youngest did not go. My oldest took her foot off the brake and "tapped" the car in front of her. The kia's drive side air bag partially deployed injuring my daughter's hand slightly. She immediately drove it home (with inoperable seat belts due to deployment) and called me. We called the dealership, and they referred us to a body shop where we were given an estimate of ~$2,000 for repair. I inspected both vehicles and could not see any evidence of damage (not even a paint smudge). This was very upsetting as I am now concerned with spurious air bag deployments with this vehicle. Kia claimed that both impact and deceleration are required to deploy the air bag, my question is why did it only partially deploy ? this incident was very similar to parking a car and touching the vehicle in front of it. See photos for deployment, and no damage to front of vehicle.

The car got a flat tire while taking a curve and hit a concrete pole. The car was total loss and all the front part was smashed. The steering wheel airbag was the only to deployed but did not deploy all the way, side airbags didn't deployed. Driver got a clavicle fracture.