could you try transferring the call before you turn the key off.
Curious also about which radio you have.
edited note: I made a short video of this process. It's at the link below:
Originally Posted by firemarshallvin
So I just tried this method a few minutes ago as I got a call on the way into work. I didn't want to walk away from the rig or hang up on the caller either. I turned off the rig first, and nothing, radio stayed on and connected. Then I transferred the call via the radio to my phone (iphone 5 FYI). The radio remained active, so i opened and closed the door thinking that maybe it was still in the "on delay", and still no change. SO I stayed on the phone (handset) until it ended. As soon as the call was ended on my phone the radio shut down. Oh well, guess next time I will try walking away and just coming back after the call to confirm it shut down.