It's hard to describe, but here goes.

The Center of thrust is offset down and somewhat in front of the CG, this means high thrust imparts a pitch up moment. Small, but present.

The bigger problem is the nacelles shape though, they create body lift at high AoA; imagine a vacuum bubble trying to suck the wing/nacelle backwards forming in the airstream, "pulling" them back.

Combine both of these characteristics, and you have an airframe demonstrating near stall positive pitch instability. I.e. you get a moment that if left uncountered will reinforce itself until the plane ends up stalling; behavior completely unprecedented in the airframe.

So in order to "counter" this behavior an automated system was introduced which supposedly restored the pilot relative flight characteristics in line with the old airframe's specs.

I'm probably oversimplifying, but it's the closest I can get to a visualization that makes some sense.