Database agent cannot be remove from monitoring due to the error: 'Agent is not registered' (4249934)

Database agent cannot be remove from monitoring via the Databases dashboard due to the error 'Agent is not registered'.

Error in MangementServer log:
VERBOSE [cvqztrwfrc:612352999142284703465326] system._dbwc_globalview_gv202d20actions.scripts.gvActions - The operation DELETE failed on node scexpr01s: Error executing script id=system:dbwc_globalview_gv20-20actions.deleteAgentOracleRacAPI name="'deleteAgentOracleRacAPI' from the System module Databases/GlobalView/GV - Actions"

message: com.quest.nitro.service.sl.interfaces.scripting.ScriptingException: com.quest.nitro.service.sl.interfaces.scripting.ScriptAbortException: java.lang.RuntimeException: ##Agent is not registered: com.quest.nitro.agent:namespace=DB_Oracle,agentName=DB_Oracle_RAC#xxxs#xxxx-xxxx-xxxx-xxxx-xxxx,agentId=xxxx##

1. Go to Administration | Agents | Agent Status.
2. Delete the database agent.