The darn rooms turn it off when unoccupied. Modern dumb energy saving idea. Like when go into the bathroom the red light motion ceiling sensor notices you & turns on the fan. It’s not the light switch. Once return, you will notice the temp returns in a few minutes. Has some motion sensor & be sure any patio door is closed. If open, AC shuts off. If temp stay higher, not resetting, it’s a maintenance repair call issue. (Had one). They come & get up in the entry ceiling & fix it.