Short description of error
Rendering point density in Cycles is either broken or very unintuitive. A bounding box object with applied scales combined with a point density cloud made up of vertices with applied scale renders incorrectly with both Object Space and World Space selected in the Point Density node. By scaling one or the other and through some combination of applying/not applying and messing with the Space parameter I've managed to stumble across settings that "work", but following the same steps again never seems to create the same result as the previous time.
Exact steps for others to reproduce the error
Open file and render. Switch from World Space to Object Space and vice versa. Play with scales. Etc. Doesn't seem to work as expected at all.
Point cloud as seen in viewport
Rendered point cloud in Object Space (Points stretched and scattered where they shouldn't be)
Rendered point cloud in World Space (Points constrained to a tiny box that seems to have no relation to anything in the scene at all)