WAL archive messages in streaming standby server's log

For some reason, after testing failover successfully and then failing back to restore the original primary server, my
standbyserver is acting a little strange. I have the following log messages repeating every 5 minutes: 

< 2014-05-06 13:41:17.705 EDT <@> % >LOG:  restored log file "000000020000000000000046" from archive
< 2014-05-06 13:41:17.709 EDT <@> % >LOG:  record with zero length at 0/46000090
< 2014-05-06 13:41:17.710 EDT <@> % >LOG:  restarted WAL streaming at 0/46000000 on timeline 2
< 2014-05-06 13:41:17.710 EDT <@> % >LOG:  replication terminated by primary server
< 2014-05-06 13:41:17.710 EDT <@> % >DETAIL:  End of WAL reached on timeline 2 at 0/46000090.

Note that these are not shown as error messages, but it doesn't appear that WAL processing is continuing as there are
atleast a dozen newer WAL files from the primary which are not being copied into the standby server's pg_xlog
directory.I suspect the problem lies with the the second line indicating a record with zero length, but don't know how
toclear this out so it goes away - short of doing a pgbasebackup on the primary and rebuilding the standby from that. 

Anyone have any ideas?
Jay