I don't understand the following error, why would the "latest" snapshot already exist when these are created by this very auto-snap process?

REPORT: * REPORT: Appliance : myhost (OS v3.1.2, NMS v3.1.2-8147 (r9697)) REPORT: Machine SIG : 967JFAGFQ REPORT: Primary MAC : 0:25:90:14:32:ac REPORT: Reporter : services-reporter REPORT: Time : Fri Jun 1 05:01:03 2012 REPORT: Description : Services report for a configured period REPORT: *

Total for the period: errors - 0, warnings - 1

Service Log - svc:/system/filesystem/zfs/auto-snap:hg-2hour-000

[2012-06-01 00:07:35] - [WARNING] | could not create snapshot "data/backups/hg@snap-hourly-2-latest" on | "localhost": com.nexenta.nms.SystemCallError: cannot create snapshot | "data/backups/hg@snap-hourly-2-latest": dataset already exists