Earlier quoted context omitted.
Yes, but how could it relate to the nosediving by just adjusting the seat?
In smaller planes with mechanical adjustable seats instead of electrical there have been several accidents due to the seat moving unexpectedly. So much that the FAA has made regular inspection of the seat rails mandatory for a long list of Cessna models: https://www.federalregister.gov/documents/2010/11/08/2010-28...
Typically this happens during take-off when rotating. This particular failure mode doesn't make much sense for an airliner in cruise.