Splitting and renaming of the parts does not work as described

Splitting and naming of the parts does not appear to work as described.
Have a look at the attached files. Defining the split point to be d.js produces 1.js with a.js,b.js, and c.js included and a separate file including d.js. As per description of the webminifier's behaviour this should result in one file with the configured name including all the js files.