CONSTRUCT result duplicates shows [object Object][object Object][object Object]

[crapthings]

what is duplicates used for ?

I20200519-15:39:59.451(8)? {
I20200519-15:39:59.451(8)?   "triples": [
I20200519-15:39:59.451(8)?     {
I20200519-15:39:59.451(8)?       "subject": {
I20200519-15:39:59.451(8)?         "interfaceName": "NamedNode",
I20200519-15:39:59.451(8)?         "attributes": [
I20200519-15:39:59.451(8)?           "interfaceName",
I20200519-15:39:59.451(8)?           "nominalValue"
I20200519-15:39:59.451(8)?         ],
I20200519-15:39:59.451(8)?         "nominalValue": {
I20200519-15:39:59.452(8)?           "token": "uri",
I20200519-15:39:59.452(8)?           "prefix": null,
I20200519-15:39:59.452(8)?           "suffix": "a",
I20200519-15:39:59.452(8)?           "value": null
I20200519-15:39:59.452(8)?         }
I20200519-15:39:59.452(8)?       },
I20200519-15:39:59.452(8)?       "predicate": {
I20200519-15:39:59.452(8)?         "interfaceName": "NamedNode",
I20200519-15:39:59.452(8)?         "attributes": [
I20200519-15:39:59.452(8)?           "interfaceName",
I20200519-15:39:59.452(8)?           "nominalValue"
I20200519-15:39:59.452(8)?         ],
I20200519-15:39:59.452(8)?         "nominalValue": {
I20200519-15:39:59.452(8)?           "token": "uri",
I20200519-15:39:59.452(8)?           "prefix": null,
I20200519-15:39:59.452(8)?           "suffix": "plays",
I20200519-15:39:59.452(8)?           "value": null
I20200519-15:39:59.453(8)?         }
I20200519-15:39:59.453(8)?       },
I20200519-15:39:59.453(8)?       "object": {
I20200519-15:39:59.453(8)?         "interfaceName": "NamedNode",
I20200519-15:39:59.453(8)?         "attributes": [
I20200519-15:39:59.453(8)?           "interfaceName",
I20200519-15:39:59.453(8)?           "nominalValue"
I20200519-15:39:59.453(8)?         ],
I20200519-15:39:59.453(8)?         "nominalValue": {
I20200519-15:39:59.453(8)?           "token": "uri",
I20200519-15:39:59.453(8)?           "prefix": null,
I20200519-15:39:59.453(8)?           "suffix": "管理员",
I20200519-15:39:59.453(8)?           "value": null
I20200519-15:39:59.453(8)?         }
I20200519-15:39:59.453(8)?       }
I20200519-15:39:59.453(8)?     }
I20200519-15:39:59.454(8)?   ],
I20200519-15:39:59.454(8)?   "duplicates": {
I20200519-15:39:59.454(8)?     "[object Object][object Object][object Object]": true
I20200519-15:39:59.454(8)?   },
I20200519-15:39:59.454(8)?   "actions": [],
I20200519-15:39:59.454(8)?   "length": 1
I20200519-15:39:59.454(8)? }