If a PropertySelect is assigned a select query with ordering, it will still apply ordering by option label as well, which may lead to duplicate columns in the ORDER BY clause.

PropertySelect.loadOptionList():
...
            if (getSelectQuery() != null) {
                SelectQuery query = getSelectQuery();

                if (getOrdering() != null && !orderingApplied) {
                    query.addOrdering(getOrdering());
                    orderingApplied = true;

                } else if (getOptionLabel() != null && !orderingApplied) {
                    query.addOrdering(getOptionLabel(), true);
                    orderingApplied = true;
                }
...