The FTP Agent is not visible in the Client 0 Agent list.
The agent is up and running and can be seen via the Serice Manager GUI.
FTP job associated with the agent could run successfully although any attempt to modify the attribute or creating a new job with the agent was not successful due to not able to select agent (when select the host in the FTP job - the FTP agent name no longer appears and no jobs can be created against it because it is not a known agent/host).
For some reason, the GUI does not recognize the agent object for that agent.
Automation Engine 10.0.4
The solution is similar to creating new agent entry, please see following documentation for more details
Installing/Upgrading the FTP agent