Pareto solutions are found below true PF in case of 3D DTLZ1 problem. Whereas they are found above true PF in case of 2D DTLZ1 problem.
I have checked and confirmed problem formulation and variable bound. ( variables used are 3).
Algorithm converges on DTLZ-2, 3, 4.
What might be the cause or area of improvement in MO algorithm.
Reference: Deb K., Thiele L., Laumanns M., Zitzler E. (2005) Scalable Test Problems for Evolutionary Multiobjective Optimization. In: Abraham A., Jain L., Goldberg R. (eds) Evolutionary Multiobjective Optimization. Advanced Information and Knowledge Processing. Springer, London