This is the rolled-up 'fsmDescr' carried directly on the Server Discovery Policy object, describing the most recent asynchronous workflow UCS Manager ran against this specific policy, such as propagating an action change to affected servers. Because it lives on the policy object itself rather than in the detailed ServerDiscPolicyFsm sub-object, it's the fastest place to see what the policy was last doing without walking the separate Fsm/Stage/Task history. Right after an admin switches the action from UserAcknowledged to Immediate, this might briefly read "Propagating discovery policy change to pending servers".