The bank claimed in a media statement today that when the IDMs were rolled out in May 2012, they were working as they should.
A software update later that year led to the machines not providing the correct Threshold Transaction Reports which had to be sent to AUSTRAC.
Last week, AUSTRAC initiated civil action against the bank in the Federal Court, alleging that a total of $77 million had been laundered through the bank.
CBA said that the error with TTRs became apparent in 2015 and within a month of finding out, it informed AUSTRAC, delivered the missing TTRs and fixed the coding error.
Bank chief executive Ian Narev has been making the media rounds this morning, but has refused to accept blame for the alleged mistakes and step down.