Extract from the ACCIDENT REPORT:
"According to the aeroplane’s manufacturer,
the autopilot was most likely automatically disconnected due to
differences in the pitch servo commands. The aural warning remained
active for the next 18 seconds."
There were three pilots on board, PF, PM and AP. Once the one who did all the work decided to quit the job, the other two could not handle the situation. I put it down to yet another case of total capitulation to automation.