Where is your proof of that? Aren't you outside your area of expertise?Computer simulations of complex systems - even the three body system - are progressively less reliable the further forward you predict.
Obviously the collisions of point masses under an inverse square force would be a problem so, as they say, "Don't do that."Where bifurcation events can occur - and they can in almost any complex system, predictability falls to zero pretty quickly. Your only hope of perfect prediction in that case would be perfect measurement. Heisenburg rules that out anyway.
Once again you have forgotten that you have misunderstood the physics of a Newtonian universe. Just as soon as you specified the mathematical model to be Newtonian, then the subject had nothing to do with the Heisenburg universe and the measurement problem.