CMK2.1.0p3 - REST API error with effective_attributes

**CMK version: 2.1.0p3
**OS version:ubuntu 20.04

**Error message: This is an error of the implementation.

This is an new issue since 2.1.0p3!
Error occurs: When a host have additional “custom host attributes” configured
to produce this: query the REST-API: /api/1.0/objects/host_config/switch2?effective_attributes=true
I received the right result, also with the custom-attribute but the API says:

  "title": "Server was about to send an invalid response.",
  "status": 500,
  "detail": "This is an error of the implementation.",
  "ext": {
    "errors": {
      "p_kuid": [
        "Unknown field."
    "orig": {
      "domainType": "host_config",
      "id": "switch2",
      "title": "switch2",
      "links": [
      "members": {},
      "extensions": {
        "folder": "1_kunden-monitore/",
        "attributes": {
          "ipaddress": "",
          "meta_data": {
            "created_at": 1656320064,
            "created_by": "cmkadmin",
            "updated_at": 1656320107.7524633
          "p_kuid": "22222"
        "effective_attributes": {
          "meta_data": {
            "created_at": 1656320064,
            "created_by": "cmkadmin",
            "updated_at": 1656320107.7524633

Hi all,
this seems to be solved with 2.1.0p4
Thanks to the one who did this :slight_smile: