The following documentation (https://docs.openshift.com/container-platform/4.12/post_installation_configuration/machine-configuration-tasks.html#what-can-you-change-with-machine-configs) says that we only support changing SSH keys for core user, but it doesn't explicitly mention that we don't support adding users other than core.

4.12 (impacts all the 4.y versions)

Always

1. Read the docs
2.
3.

Wrong docs

Right docs