(nearly) identical results for repeated mixes

Hi,

I've got a recipe I've been using for a while:

{
  "artist": [
    "yes",
    "genesis",
    "pink floyd",
    "king crimson",
    "emerson lake and palmer"
  ],
  "description": [
    "art rock",
    "progressive rock",
    "british rock"
  ],
  "type": "artist-radio",
  "variety": "1",
  "distribution": "wandering",
  "artist_start_year_after": 1971,
  "artist_end_year_before": 1989,
  "bucket": [
    "id:deezer",
    "tracks"
  ]
}

Today this always would return Yes' "Roundabout" or "Owner of a lonely heart", followed by Genesis "Land of Confusion" or "That's all", and Pink Floyd's "Wish you were here" or "Comfortably numb" as the first tracks. I've run this mix a few dozen times, always with the same results. I varied the bucket between deezer, spotify, rdio and 7digital. Didn't help.

Is there something wrong today? With me, the recipe or your magic?

Michael