There’s a Relay-specific setting similar to the client’s Command Polling setting. See https://www.ibm.com/developerworks/community/wikis/home?lang=en#!/wiki/Tivoli%20Endpoint%20Manager/page/Configuration%20Settings
You may need to configure a value for
_BESRelay_GatherMirror_UpstreamCheckPeriodMinutes
I needed that in a case where the relay could not receive the UDP pings from its upstream relay. Not sure whether this is the case for you - if so I really wouldn’t expect the client to pick up the action when you restart the client service, but it might be worth checking whether it helps.