Door ajar only in hot weather

Up to about a shady 70 degF the door ajar stays off and the Smart Key works fine. About 75 deg the door ajar light comes on sometimes and flashes. The Smart Key works fine even with the light on. A little hotter and the Smart Key won't open or close the doors. The door ajar light stays on. The remote lock/unkock works OK. A little hotter the remote won't work at all, but I can lock the car with the lock buttons on the doors inside the car. A little hotter and the manual key is the only way to lock or unlock the car. Once inside the car the Smart Key works fine to start and run the car regardless ot the flashing (cooler) or solid (hotter) door ajar light. I replaced the 12v battery with a new Optima battery and now I can let the car sit for more than 3 days but less than a week before the 12v battery won't work. I have not disabled the Smoart Key function.