Icingabeat equals issue

i have icingabeat set up from a master to a kafka cluster and am trying to set the severity to be text and not number e.g. 0=OK, 1=WARNING, 2=CRITICAL. i’m using the add_field processor to add/set the field but the equals condition doesn’t work but the range does:

  - if:
      range:
           icinga.chk_state.gte: 0
           icinga.chk_state.lt: 1
    then:
         - add_fields:
              target: icinga
              fields:
                 chk_severity: OK
  - if:
      equals:
          icinga.chk_state: 2
    then:
         - add_fields:
              target: icinga
              fields:
                 chk_severity: CRITICAL

output:

{
  "@timestamp": "2021-01-26T15:52:37.258Z",
  "@metadata": {
    "beat": "icingabeat",
    "type": "_doc",
    "version": "7.5.2"
  },
  "host": {
    "name": "icinga-temp-m1-aberdeen"
  },
  "icinga": {
    "host": "vip-lb-sand.pete.com",
    "service": "Capacity Sand",
    "timestamp": "2021-01-26T15:52:37.257Z",
    "type": "CheckResult",
    "check_result": {
      "exit_status": 2,
      "output": "HTTP CRITICAL: HTTP/1.1 503 Service Unavailable - 282 bytes in 0.121 second response time "
    },
    "chk_state": 2
  },
  "type": "icingabeat.event.checkresult",
  "datacenter": "m1-aberdeen",
  "env": "temp"
}
{
  "@timestamp": "2021-01-26T15:52:38.742Z",
  "@metadata": {
    "beat": "icingabeat",
    "type": "_doc",
    "version": "7.5.2"
  },
  "icinga": {
    "chk_state": 0,
    "chk_severity": "OK",
    "timestamp": "2021-01-26T15:52:38.740Z",
    "type": "CheckResult",
    "check_result": {
      "exit_status": 0,
      "output": "Icinga 2 has been running for 21 hours, 49 minutes and 1 second. Version: r2.11.2-1"
    },
    "host": "icinga-temp-m1-aberdeen",
    "service": "icinga"
  },
  "type": "icingabeat.event.checkresult",
  "env": "temp",
  "datacenter": "m1-aberdeen",
  "host": {
    "name": "icinga-temp-m1-aberdeen"
  }
}

i have icingabeat version 7.5.2 (amd64), libbeat 7.5.2 [6a77caeb37c55edce8e5e321e0334084c61a7761 built 2020-02-27 11:09:37 +0000 UTC

any thoughts/ideas would help.