Kia Troubleshooting Questions? Ask a Mechanic
If I had to guess, I would say that you have a failing crankshaft position sensor. It needs to operate within a certain resistance range, and as the vehicle heats up, it may wander above this range, and stall the engine. And for some reason, since the engine dies at that time, it does not store a fault. because with the engine not running it is perfectly normal not to have a signal from the crank sensor!