Have you checked the steps at Troubleshooting Client Reponsiveness that is linked earlier in the thread?
Especially regarding GatherHashMV messages in the client log. You’ll want to ensure a firewall, or host-based firewalld, is not blocking the notifications from parent relay to child when new actions are taken.
What could be misleading is seeing the message immediately after a command poll or site gather from the client. You want to see the message within a few minutes of taking the action, not related to a relay select, site gather, or command poll.