Quite few sites have few entries in APEL that don't quite match. They can appear with two messages
OK [ Minor discrepancy in even numbers ]
WARN [ Missing data detected ]
They don't look good on the Sync page and nagios also sends alerts for this problem which is even more annoying.
The problem is caused by few records with the wrong time stamp (StartTime=01-01-1970). These records need to be deleted from the local database and the period were they appear republished with the gap publisher. To delete the records connect to your local APEL mysql and run:
mysql> delete from LcgRecords where StartTimeEpoch = 0;
Then for each month were the entries appear rerun the gap publisher. And finally rerun the publisher in missing records mode to update the SYNC page or you can wait the next proper run if you are not impatient.
Thanks to Cristina for this useful tip she gave me in this ticket.