I'm using DiodeDynamics switchbacks on my '12 Fusion Sport, and yes they are a little pricey but do function perfectly. The fit of the bulb to the socket was not as snug as the OEM bulbs, I used heat shrink as a precaution. So far so good.
I have had this problem on my '11 and '13. The dealer work orders indicate they cleaned the contacts on the latch assembly. Over 4 years later the '11 hasn't thrown that message again. The '13 had the contacts cleaned about 2 months ago.