After replica set failover, why do I see about 30 "ReplicaSetMonitor::_checkConnection:" messages per second in my mongos log? This seems to go on until I fail back to the original master. Here's an example message:

Wed May 4 23:09:52 [conn1] ReplicaSetMonitor::_checkConnection: mongodb05.example.com:27018

{ setName: "2", ismaster: true, secondary: false, hosts: [ "mongodb05.example.com:27018", "mongodb04.example.com:27018" ], arbiters: [ "mongodb06.example.com:27018" ], maxBsonObjectSize: 16777216, ok: 1.0 }