It's not a bug but it is a limitation. The items you actually select on a figure in "light only" dialog box are actually the bones, not the geometry.  The character is treated as a single piece of geometry in Carrara which is why it shows up as "model" in the hierarchy above the Hip bone in the properties palette. 

A work-around for this to add a spot light with a point at behavior and a very narrow beam. You can scale the spotlight to make it more manageable in front of the characters face. You can parent it to the eye to make things easier.

Mark