Right, that's not a bug, it only gives you the part data if you actually get a proper parse scan. Some NPCs don't give you that (like Svarog). parse_system is useful for getting part info from bots that have no special scan data but do have truly unique parts. NPCs like Svarog actually don't have any real special gear--they're all prototypes you can find elsewhere, so there isn't as much need to get that through parse_system.
(Notice that your scan results window did not list parts like it normally does against most bots.)