RE: Deduplicate issue in Transform and Cleanse

I had some time today to look at this. I get the same ending result set as you do but in a different order. I start the Transform and Cleanse session by ordering my result set this way. 

SELECT accountNumber 
, createdDate
FROM AutoRange_DeDup_test 
ORDER BY accountNumber ASC
, createdDate DESC

I then debup by account number. This gives me the same result set as you have. Have you started your T & C with a ordered query?