I put a new AGM battery in last week, the car was at approx 11.8 volts when I started it. It started without issue. The voltage immediately went up to 13.6-13.8volt range. It stayed at or above 13.6 volts while running. I had the heat and rear defrost running. Approximately 5-7 minutes of driving later I came to a stop at an redlight and when I went to accelerate I noticed that the engine was off and numerous dash lights were on. Shifting into park to turn the car on and off allowed it to immediately restart.
Any thoughts on why this may have occurred? **** was scary.