Praefect doesn't start pointing to new gitaly VM after switching gitaly's FQDN

I am trying to implement a simple gitaly cluster following this doc - Configure Gitaly Cluster | GitLab. I have set up one node for each gitlab, praefect and gitaly and have setup their FQDNs. Praefect is communicating with gitaly using its FQDN.
I am able to successfully deploy the setup and it is working fine.
But when I switch gitaly’s FQDN to point to a new gitaly VM (as part of Corporate Security requirement we have to replace VMs every 14 days on our cloud provider), praefect doesn’t start pointing to the new gitaly VM as new gitaly VM doesn’t start receiving praefect health check logs and old VM continues
to get health check logs from praefect unless I do gitlab-ctl reconfigure on praefect node. Couple of questions here:

  1. Why is Praefect’s reconfiguration needed as nothing changes in gitlab.rb of praefect?
  2. Should praefect not start pointing to new gitaly VM automatically after gitaly’s FQDN switches to a new IP address?