The stalactite in question is on the upper-right side of this screenshot. I moved a few steps forward and the object was no longer drawn fullbright.
![Image](http://i.imgur.com/eKHYhLo.png)
![Image](http://i.imgur.com/d8jMF0I.png)
There is another on the left that seems to stay bright no matter where I position myself. Both stalactites should not be illuminated - in every other port tested: PrBoom+, GLBoom+, Eternity, ZDoom and GZDoom, this was not the case.
This image shows the placement of the thing in the editor. It overlaps the liquid slightly, but for all intents and purposes it's still in the ground sector.
![Image](http://i.imgur.com/NbheDjv.png)
Config file attached, if it helps.