Parsing json array variable into body request results in NULL

In postman flow i created a chain where I assign variables from my GET request in order to use them in my next POST request

A sample of the POST body request:

    "metadata": {
        "configurationVersions": [
        "clusterVersion": ""
    "id": "f0ec694c-c89e-4735-8821-5f082c522ecf",
    "name": "Host",
    "description": null,
    "rules": [
            "type": "HOST",
            "enabled": true,
            "valueFormat": null,
            "propagationTypes": [],
            "conditions": [
                    "key": {
                        "attribute": "HOST_OS_TYPE",
                        "type": "STATIC"
                    "comparisonInfo": {
                        "type": "OS_TYPE",
                        "operator": "EXISTS",
                        "value": null,
                        "negate": false
    "entitySelectorBasedRules": []

Variables assigned:

POST Pre-request Script:

POST body:

Requst Body:

How can I parse the rules and avoid the null value?

What environment are you setting the variables from the GET response body? Or what would you see if you console logged rules on line 3 in the Pre-req script?

Additionally, it is not necessary to assign the rules or entity to the environment scope since the value is used within the run you could assign it to local scope using pm.variables.set(name, value)