BRE
I'd heard that this was an autothrottle problem. Which might be electrical. But the sources linked here state that the current problem (sorry about that
) is related to the electrical power system. That is common to so many aircraft systems that it would be hard to believe it would be missed on the SJ182 flight data recorder.
That Boeing says this problem might affect "certain Max planes" makes me think that it is either related to a particular power system option. Or due to a design change/manufacturing problem affecting a range of the production line sequence.