How to create a static playlist both seeded by and limited to a catalog?

I am also trying to do something very similar and getting either empty or almost empty playlists. My query is:

http://developer.echonest.com/api/v4/playlist/static?api_key=MYKEY&results=50&type=catalog&format=json&seed_catalog=CAPYHWY14291E7B5CE&bucket=audio_summary&bucket=id:CAPYHWY14291E7B5CE&limit=true&max_tempo=100&max_energy=0.3

I see from the previous posts, they were some time ago. Has the same bugs re-appeared recently? The above query used to work a few months ago with great results.

Am I doing anything wrong?