An update on this situation. I did a resync several days ago and thought all was well but last night the player stayed on after I switched the key off again. After waiting about 45 seconds, the unit did finally power down by itself.

I took the car back to the installer and had them double check everything and they could find nothing wrong installation wise. They were pretty thorough and I trust these guys 100% so I think I can rule out an installation issue.

As Tony said above, it's probably Problem #1 giving me grief. It's funny how this problem NEVER happened in my previous vehicle, though but seems to do it constantly in the new car.