2007 Ford Escape Lighting problems

The passenger rear right brake/tail bulb went out, when I went to replace the bulb I found that the socket was burned, very dark brown splotchy areas, and had a distinctive odor. I checked the left, driver side and found that the socket on that brake/tail light was also turning brown at the pin site. It concerns me that I am finding this issue to be a consistent problem around the internet.

I have had my vehicle in the shop three times in the last month. It is currently in the shop for over a week now because the interior lights keep malfunctioning. They may work for a week or a few days then they malfunction again. Several things has been replaced, the last one being the overhead light assembly, but the problem has not been corrected. All the interior lights fail to work except for the instrument panel. *Tr