Replaced both rear brake light bulbs with 4157k bulbs purchased at a national auto parts store. Within a week both burnt out. Checked both bulbs and they appeared to have overheated and the plastic at the base was melted. Checked with Ford service and they have a service bulletin (20626) that discusses the tail light concern and recommends not using after market bulbs and replace with Ford part 9T4Z-13466-A. The Ford parts guy didn't have it in stock and said that I was the first person to order this new bulb. Makes me wonder if there is an electrical wiring issue in the rear tail light assembly.
