I believe this was covered already under here...
http://www.ft86club.com/forums/showt...ght=tail+light
I have this same issue and I got the dealer to replace the lights but it came back, so I'm going back to get it fixed again since it's all covered under warranty. If you want you can have your dealer try to fix it via this TSB.
http://www.ft86club.com/forums/showthread.php?t=21868