All jet airliners have a tendency to pitch up under thrust, because of the low position of the engines. The 737 Max has a whole other issue separate from that, caused by the aerodynamic effects of the engines placed far forward of the wings. Airplanes are not allowed to pitch up more unless the pilot applies progressively more and more backward stick force. The 737 Max has a tendency in certain conditions (high angle of attack) to pitch up even when the pilot keeps applying a constant force.
Some people argue that that behavior, without measures to prevent it, would disqualify the plane from certification completely. Others say that those measures are only needed to keep the Max under the same type rating as previous 737 generations. I'm inclined to the former, but I'm no expert so that's certainly not definitive.