Yep, best fix I found:
"Mine forgets the USB sometimes too. What I do, so I don't have to dig around in the console, I just push the sync
button on the wheel and tell her USB or Play USB . Then she finds it."
2011 Mustang V-6 Premium Convertible, 5-11-2010. Paid $800 on 09-19-14 to replace hood with paint bubbles, traded car for a Chrysler later same day