Unreal light

I'm watching a Bob Ross show (call me a glutton for punishment). He's painting a night scene in an oval shape, with purple misty trees in the background and a green meadow.

The lavender trees started out looking vaguely plausible -- until he put in entirely too many highlights for a misty, foggy night; and it looks even worse now that the meadow is in. The grass is much too visibly green for a night scene. And you can't tell where the light is coming from -- it's sort of emanating from the center of the painting, but then the highlights on the trees and grass etc. are all wrong. I think one of my art books called that "jumping the light", i.e., having light that comes from several different directions at once. And that seems to be a consistent problem with Ross's paintings. The mountains may have highlights, but the trees and bushes have inconsistent highlights, and may or may not have shadows at all.

This painting, in particular, reminds me of the post I stumbled across on Danny Gregory's blog where someone mentions that a friend painted a UFO into a Bob Ross-style painting. The UFO, beaming light down onto the grass, is the only thing that would make the light in this painting make sense.