So an interim report by the Nigerian authority suggests the ditching was in response to problems with the AFCS. The commander decided to ditch rather than risk losing control of the aircraft presumably.
therein seems to lie the problem TT - was it a well-trained and professional crew taking wise precautions faced with an unusual or complex emergency? Or was it poor knowledge of the systems and lack of captaincy leading to an unnecessary water landing?
Until (and if) the full details of the malfunction are made public then the speculation will continue.