The SQL page does more work, it also asks
select dbms_metadata.GET_DDL ('TRIGGER', trigger_name ,owner ) from Dba_triggers where table_owner = :OWNER and table_name = :NAME
which finds the trigger attached to the table (which in this case, is the view)
The Export feature is NOT making this call, which would get the trigger.
SELECT dbms_metadata.get_dependent_ddl('TRIGGER', 'V_DUMMY') from dual;
I'd call this a bug.