mod_cluster add-proxy and remove-proxy CLI commands are not persisting changes to the configuration

Issue

• mod_cluster add-proxy and remove-proxy CLI commands are not persisting changes to the configuration. I use a command like the following to update the proxy-list:

  /subsystem=modcluster:add-proxy(host=127.0.0.1, port=6667)
  

  I can see the change applies immediately, but the config is not changed and the updated proxy-list is lost after restart.