Phone making calls by its self

A

AC Question

One three occasions I have found out that my phone has made late night phone calls seemingly by its self. The first time a friend called me in the morning, and asked why I called him at 4:30am. I told him that I hadn't and sort of blew it off. I sleep with my phone next to my bed, and assumed I somehow hit the phone/screen just right and called him accidentally while sleeping. The other two times, I called my wife's phone, she was sleeping next to me. She confirmed that I was sleeping, and that my phone was still sitting on my night stand at the time.

The only similarity I can find is that in all three cases, the phone redialed the last number I called before going to bed. I downloaded AVG and malware bytes and ran a scan with both, and neither reported and type of infection/compromise. Anyone have any ideas either on the cause, or just a way to fix it