If you have upgraded Maestro for Open Systems to version 1.5.6 through 1.5.9 and have schedules defined to launch with a calendar that contains either an include or exclude of a datelist or calendar command, there will be duplicate entries in the Maestro launch table. If the date or time of one of those schedules is changed, it will cause the schedule to launch twice.
Log into SupportPlus to download the patch or the latest release of Maestro for Open Systems version 1.5.10