When dates and times are sent to the database from procedures, they are sent as strings. The date part of the string is interpreted according to the current setting of the date_order database option. As different connections may set this option to different values, some strings may be converted incorrectly to dates, or the database may not be able to convert the string to a date.
You should use the unambiguous date format yyyy-mm-dd or yyyy/mm/dd when using date strings within procedures. The server interprets these strings unambiguously as dates, regardless of the date_order database option setting.
For more information on dates and times, see Date and time data types.