You might want to check your settings like your timer perhaps or if all else fails contact paranormal investigators lol but for real Iwould definitely start with the settings first.
Need to confirm are you referring to the q80a? Until a reply I will assume you are Try this Settings-> General -> Network -> Expert Settings > "Power On with Mobile" and turn it OFF
Mine has the same problem. It automatically turns on into ambient mode. I guess I enabled some settings but don't remember anything. If anyone know please post.
