elasticsearch - Wrong sum with aggregations -

i'm trying run query:

get my_index/_search {   "size": 0,   "query": {     "bool": {       "filter": [         {           "query_string": {             "query": "_exists_:products_count",             "default_operator": "and"           }         }       ]     }   },   "aggs": {     "pid": {       "terms": {         "field": "pid",         "size": 15,         "order": {           "products_counter": "asc"         }       },       "aggs": {         "products_counter": {           "sum": {             "field": "products_count"           }         }       }     }   } } 

the results are:

{   "took": 5,   "timed_out": false,   "_shards": {     "total": 12,     "successful": 12,     "failed": 0   },   "hits": {     "total": 489681,     "max_score": 0,     "hits": []   },   "aggregations": {     "pid": {       "doc_count_error_upper_bound": -1,       "sum_other_doc_count": 488443,       "buckets": [         {           "key": 3229479298,           "doc_count": 14,           "products_counter": {             "value": 26           }         },         {... 

although results pid returned 188 , not 26. if raise size of aggregation 15 100000 example right number. understanding , fixing problem?