Couldn't it be after a sabre throw? I definately remember from somewhere that if it couldn't make its way back to you it just drops to the ground and you have to pull it back 'unlit'. I think there was a jk mod like this or it happened in MotS. After all thats what happened to Vader in the films, he had to pull the hilt back unlit after throwing it.
Stockport County forever (please don't laugh)