Search Guard versions before 24.0 had an issue that values of string arrays in documents are not properly anonymized. References: https://docs.search-guard.com/6.x-25/changelog-searchguard-6-x-24_0 https://search-guard.com/cve-advisory/
Field level security was added in Search Guard 5 which is used by OpenShift 3.11, and 4.1, but not earlier versions.