The rule says that two properties on the agent must meet certain conditions. Both of those properties are updated by either an 'update server properties' job or by right-clicking on the server object and choosing 'verify'. probably what has happened is that the last time the USP ran, the agent was offline, so the 'AGENT_STATUS' property was set to 'agent is not responding'.
you should probably take out the 'AGENT_STATUS' condition from the discovery rules.
Thanks Bill !!
I did run an ad-hoc job of USP on these 2 server and it worked perfectly.