Vehicle was stored in a closed garage prior to operation. I started the vehicle and began to back out of the garage into the driveway. After approximately 3-5 feet of movement backward, several yellow warning icons illuminated on the dashboard and the vehicle’s brakes stopped functioning. The vehicle free-rolled several feet down the driveway. After about 1 second, the vehicle brakes engaged, all warning lights went out, and the vehicle began operating normally. I attempted to replicate the fault but was not able to. I feel this is a safety concern because uncontrolled rolling of a 2-ton vehicle could cause a crash or I could have rolled over a small child or a dog on my sidewalk! Ambient temperature 56F with no precipitation and low relative humidity. Garage was at roughly 65F. Vehicle has 3,960 miles on the odometer and was at approximately 40% charge on the main battery. I am currently on hold with Kia to report the issue (20 minutes and counting).