don't worry too much about having the little light on your dash on....it won't do anything.....
as long as you know that your lights are fine, then don't worry....could be just a bad ground.
mine has the same problems, but it started after I removed the rear deck to put some sound dampening in, and I'm sure that I knocked some grounds loose when I was shoving it back in....
but eitherway, I've removed my center brake bulbs now w/o using resistors, so it'd have th problem anyway.....
I just kinda ignore it now.