Regarding your point of bigger engines, I understood it differently. The bigger engines provide a lot of thrust and with the new position of the engines, it’s

Regarding your point of bigger engines, I understood it differently. The bigger engines provide a lot of thrust and with the new position of the engines, it’s a lot easier for the plane to stall. So the plane was outfitted with a sensor and software that reads the angle of attack and it corrects it in case the plane reaches the factor of safety angle. If the sensor malfunctions, the software would get wrong readings and try to correct something that doesn’t need correction. It moves the plane nose down. Pilots correct. Process repeats. Hence the elevation fluctuations seen in Lion Air and Ethiopian Airlines.