Hello Darien,
In Pulseway 6.0 the group policy management has been moved to WebApp -> Server Admin -> Configuration -> organization / site / agent group -> Policy tab
Hello EndzoneHero,
Most probably it is due to the fact that there was no communication between the agent and PSA, hence the agent was never registered on it.
Can you navigate to your group policy and temporarily create a notification that you know will be triggered ie 'Send a notification when the system partition has less than 95%' with priority Critical or Elevated as only those two are by default picked up by PSA.
This should force registration of all your RMM agents with PSA instance.