Why does our 2018 Chevy Traverse randomly not start? Anti-theft deterrent?

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Twice after buying our 2018 Traverse, it will randomly not start when we push the button. If we get out, lock the door, wait a few minutes, then it resets itself and doors start. However, it won’t shift out if first gear and the check engine light is on. After turning it it off/on again, It will shift properly and the check engine goes off eventually. Both times, we noticed we had a child climbing in/out of the car with door open when it was being locked... wondering if there is a built in safety feature that is a theft deterrent? The dealership can’t find anything wrong with it. The battery, starter and alternator are all fine. Afraid we will get stuck on the road somewhere and it won’t start!