On a system using LOCAL authentication and with connected agents that are NOT authenticated, Agents are counted by the the telemetry nodes metrics (stored at midnight in the LAH table) even though they have the flag HOST_Authenticated set to 'N'.
Any One Automation system in version 21.0
This is a defect of the Automation Engine affecting the Telemetry feature specially.
Only agents with Host_authenticated set to yes should be counted (this includes agents manually authenticated for LOCAL).
This bug is fixed with version 21.0.9 of the Automation Engine.
Bug ID: AE-34410
Bug Title: Telemetry metric counts agents that are not authenticated