Why does adding a RHEL7 node to Red Hat OpenShift Container Platform 4.3 cluster fail with cri-o service error?

Issue

• Adding a new Red Hat Enterprise Linux 7 worker node to existing Red Hat OpenShift Container Platform 4.3 cluster fails with error below.

TASK [openshift_node : Restart the CRI-O service] ************************************************************************************************************
task path: /usr/share/ansible/openshift-ansible/roles/openshift_node/tasks/config.yml:83
Friday 17 April 2020  07:10:23 +0200 (0:00:00.721)       0:01:48.117 ********** 
fatal: [examplerhel7.sbx.paas.cirb.lan]: FAILED! => {"changed": false, "msg": "Unable to start service crio: Job for crio.service failed because the control process exited with error code. See \"systemctl status crio.service\" and \"journalctl -xe\" for details.\n"}

[root@examplerhel7 ~]# systemctl status crio.service -l
● crio.service - Open Container Initiative Daemon
   Loaded: loaded (/usr/lib/systemd/system/crio.service; enabled; vendor preset: disabled)
  Drop-In: /etc/systemd/system/crio.service.d
           └─10-default-env.conf
   Active: failed (Result: exit-code) since Fri 2020-04-17 07:13:02 CEST; 5s ago
     Docs: https://github.com/cri-o/cri-o
  Process: 124466 ExecStart=/usr/bin/crio $CRIO_STORAGE_OPTIONS $CRIO_NETWORK_OPTIONS $CRIO_METRICS_OPTIONS (code=exited, status=1/FAILURE)
 Main PID: 124466 (code=exited, status=1/FAILURE)

Apr 17 07:13:02 examplerhel7 systemd[1]: Starting Open Container Initiative Daemon...
Apr 17 07:13:02 examplerhel7 crio[124466]: time="2020-04-17 07:13:02.922224244+02:00" level=fatal msg="runtime config: conmon validation: invalid conmon path: stat /usr/libexec/crio/conmon: no such file or directory"
Apr 17 07:13:02 examplerhel7 systemd[1]: crio.service: main process exited, code=exited, status=1/FAILURE
Apr 17 07:13:02 examplerhel7 systemd[1]: Failed to start Open Container Initiative Daemon.
Apr 17 07:13:02 examplerhel7 systemd[1]: Unit crio.service entered failed state.
Apr 17 07:13:02 examplerhel7 systemd[1]: crio.service failed.