Light Problem HELP

[NYC]

Having a strange problem with my S4 Avant B7. At random times the car switches on the rear lights. Fault codes checked and comfort control box change but 2 weeks later lights were on when I woke up and battery almost flat. The car has coming home lights, DRL and auto headlights. It is not a regular thing was probably happening every week or 2 so hard to fault find. Apart from switching off all light functions then working through them one at a time I am a bit lost what to do next.

Has anyone had this problem? Please help?