Engine Overheating problem

Was caught in a large stop and go traffic jam yesterday in my '13. After ~ a half hour, engine temp. started to increase. Had to pull over and shut down to cool things off when it got into the red zone. When I turned the engine off, some coolant blew out the overfill. When the traffic started moving again, enough air was getting to the back to keep the temp in the normal operating zone.

First time with this problem. Anyone else have this problem?

As a side note, I understood the side vents were set up to automatically open if the engine temp got too high. This did not happen. Not sure if the vent operation is predicated on temp and speed.

Bring it back to the dealership. I'm sure it's still under warranty.