Child doc facet not getting terms, only counts

[Yangrui Guo]

 When I use subfaceting with Json API, the facet results only gave me
counts, no terms. My query is like this:

{
    apparels : {
        type: terms,
        field: brand,
        facet:{
          values:{
              type: query,
              q:\"brand:Chanel\",
              facet: {
                    type: terms,
                    field: madein
              }
              domain: { blockChildren : \"content_type:p\" }
          }
        },
        domain: { blockChildren : \"content_type:p\" }
    }
    }
}

And this is the results that I got:

facets={
    count=57477,
    apparels={
        buckets=
        {
            val=Chanel,
            count=6,
            madein={
                count=6

                buckets={}
            }
        }
    }
}

The second buckets got zero results but the count was correct. What was I
missing? Thanks so much!