ORA-14074: partition bound must collate higher than that of the last partition

SQL>
create table TEST_PARTITION (c1 number) partition by range (c1)
    ( partition p100 values less than (100),
      partition p200 values less than (200),
      partition p300 values less than (300),
   partition pmax values less than (maxvalue));


Table created.

SQL> select high_value from dba_tab_partitions where table_name = 'TEST';

HIGH_VALUE
--------------------------------------------------------------------------------
100
200
300
MAXVALUE

SQL> alter table test add partition p40 values less than (400);
alter table test add partition p400 values less than (400)
                               *
ERROR at line 1:
ORA-14074: partition bound must collate higher than that of the last partition

SQL> alter table test split partition pmax at (400) into (partition p400, partition pmax);

Table altered.

SQL> select high_value from dba_tab_partitions where table_name = 'TEST_PARTITION';

HIGH_VALUE
--------------------------------------------------------------------------------
100
200
300
MAXVALUE
400