I don't think there is the problem. I think there is no kbus wire to the trunk lid. With the exception of the reversing light all the lights on the outside work ok. Reversing light is triggered via telegram over kbus to the LCM.
As I said something must be wrong with kbus, either on the LCM side, KOM instrument cluster side or something disrupts the bus.
I think signal level peak to peak voltage is to low, but I have no way to confirm that.