Lighting effects on different tilesets

I've noticed that the "pool" of light that lights create is only visible on tilesets that change appearance with time of day. If you place a "torch glowing" doodad on a dungeon tilesetted map, then it may illuminate surrounding models, but it WON'T make the "pool of light" effect (which I suddenly realizing is blizzard cheating and changing the time-of-day in that immediate area). Oddly, even if I import a tile that is from a different tileset, it retains this property.

Is this information contained in a slk someplace? I'd love to hear anything about this. Thanks.