Answer
It is caused by different format of "minDate"/"maxDate" and "format" parameters of the {date-data} macro.Example:
Examples
{date-data:name=DateReleased|minDate=01/01/2012|format=dd MMM yyyy\}\{date-data\} |
...
{date-data:name=DateReleased|minDate=01 Jan 2012|format=dd MMM yyyy\}\{date-data\} |
...
{date-data:name=DateReleased|minDate=01/01/2012|format=dd/MM/yyyy\}\{date-data\} |
...