I had a similar situation in my past truck, except it only did it if I used the remote start, never figured out why that was the case.
Now that I have had more time to think, I need to go back and double check. I remember when I was finding the issue where water got into the VHF deck that fried the KRK15 and the BT/GPS board, and was checking voltages, that 1.5v was still running through all decks.
I need to pull the ignition sense bus fuses to verify that there is greater than 0 volts on that line, or if its a back feed from the RF decks. If the latter, I have some troubleshooting to do.
I did flash firmware to 5.13 because of a mismatch of newer coming on the HHCH, I can't remember what I had on there before. I only recalled because I had to match firmware on the decks in my other install when I swapped to the 20R control head (those decks had 5.10), I don't usually update unless there is a reason.