Create Table Not Replicating SQL Select Results?

I have a SQL statement that returns a set of columns...but...when I create table as <SQL statement> I get the same columns but with 2 of the columns containing each others data, e.g:

SQL Select:

COL1 COL2 COL3 COL4
___________________________________
AND10200000017805CG-4CG-3

Create Table as <SQL Select>:

COL1 COL2 COL3 COL4
___________________________________
AND10200000017805CG-3CG-4

The SQL Select is correct and the Create Table As <SQL Select> is wrong.

Here is my SQL:

Create table ALTERNATENUMBERS as
SELECT ctry,
id,
MAX(DECODE(tp,'EN', RN)) EN,
MAX(DECODE(tp,'RN', RN)) RN,
MAX(DECODE(tp,'AN', RN)) AN

[code]....

Unfortunately I cannot give you any data (too much of it) and small scale testing works, it's only when I run it on the 11million records do I get some (not all), just some of the data being mixed up between columns.

Now, I've tried:

1. Using SQLPLus - no joy

2. Creating the Table and then inserting the data into a blank table - also no joy

3. Using a VIEW - no joy, listagg doesn't work in VIEW tables

I do understand that without data it's hard to replicate the issue but why this statement works as a SELECT but when written to a table has data anomolies?