DEFAULT_LENGTH changed for column with CTAS

Hi,

My database version is 11.2.0.4

I have created a table with CTAS from existing table and then applied default constraints on three column having data type TIMESTAMP(6). When compared default_length column from dba_tab_cols shows difference for original table and new table. For new table default_length is reduced. Does it has any impact on data insertion and how can I fix that.

Steps I did

1) Created new table using existing one.

create table tst_default_length_issue as select * from my_table where 1=2;

2) Set default values for column on new table

ALTER TABLE tst_default_length_issue MODIFY EFFECTIVE_FROM TIMESTAMP(6) DEFAULT TO_DATE('01-Jan-0001');