It is difficult to read the AAIB supplementary report without gaining the impression that they were somewhat peeved to have been required to write it. It does not evidence their customary open mindedness, instead reeking of a desire to bury CI by whatever means they can. It seems to start from the premise that it doesn't exist, and seeks out all the material they can find to support that premise.
For my own part, I have no idea whether there is such a thing as CI or not, but having had the subject raised by this tragic series of events, I remain unclear whether it does or not. The AAIB supplementary report reads rather like a publication of the flat earth society; "The earth is flat, and here is all the evidence we have found to support this view........" and has not dispelled my curiosity.
As it transpired in court, it didn't matter what the AAIB thought, but just what the Jury did. That they could conceive of the possibility that there could be a state of mental impairment with onset ahead of the currently fully accepted stages of mental impairment does not seem at all unreasonable, and rather more to their credit than the AAIBs latest contribution is to theirs.