Any place that specifies a date in a seed xml *must* also specify a timezone. If you do an install on one machine, then do a dump/copy/import on another machine, that is in a different timezone, then reimport the original seed xml, the timestamps will not match.
What happens, is that there is no timezone on the fromDate fields. The original import uses the timezone of the local machine as the default in this case. When the seed xml is reimported on the second machine, it uses the default timezone of the second machine. If the timezones are different, then the fromDate will be different as well, and you'll get duplicate records in the database. The fix here is to update all the seed xml files to specify a timezone. Probably using UTC would be the sensible approach.
