It looks like smart playlist aren’t supported via the API yet… The “Not Found” title is return via the API.
COMPLETE Success [204]: {"items":[{"title":"Not Found","subtitle":null,"image_key":null,"item_key":"12:0"}],"offset":0,"list":{"level":1,"title":"Smart Test","subtitle":"39 Tracks","image_key":null,"count":1,"display_offset":0}}