Just to check things: Make a test map and put some lights around. Then go to World and dial midnight. You should see the circumference of light around each light. You do? then go to your map and play with height adjustments at each light. You don't ? Boy! there is some problem-s. But try the above first.
Actually I have noticed something to this effect ever since the latest patch. I had yard spotlights set up before the patch, and they shines perfectly. Now they don't. The only thing that shines is that streetlight that was mentioned earlier.