Global changes to the agent properties in dashboard listed below does not update existing agents.
Dashboard | Administration | Agents| Agent Properties | <select_Agent_type>
This is a by design. The existing agents has customized properties such has specific host names and other fields, therefor they will not be modified by a global change.
Dashboard| Administration| Agents| Agent Properties| <select Agent>
Ensure the global settings are set prior to agent creation
Pre-existing agents will need to be modified individually