wrong result after insert or CTAS into table with more than 255 columns on 18c ?

Hi,

The data changed during insert or CTAS in our test.

I found this strange result on our 18.6.0 environment.

I found the same on LivSQL 19c.

I did not find wrong result on our 12.1 DB.

I did not find wrong result, when I used less than 256 columns.

Please check the code for mor details:

SQL> prompt --create a table with more than 255 columns (TMP1)

--create a table with more than 255 columns (TMP1)

SQL> create table TMP1 (F1 varchar2(10 CHAR));

Table created.

SQL> begin

  2    for i in 2..258 loop

  3      execute immediate 'alter table TMP1 add (F'||i||' VARCHAR2(10 CHAR))';

  4    end loop;