Genetic Algorithm does not produce the requires number of individus

I'm doing an optimization with ga modulus, using the vectorized option for objective function and non-linear constraints. My function receives the entry matrix and does several finite elements meshes and solve them on a finite element software. If I input a test matrix (without the ga modulus) it will solve each element (line) and return their respective objective value. Nevertheless, when I use this function as an input function to the genetic algorithm with a non-linear constraint function, it doesn't input to the function (which is vectorized) the number of individus that I had specified. Generally on the first two generations it inputs only 1 or 2 individus, and after a bigger number, but not always the specified one. Does anyone has a clue of what might be the problem? Thanks a lot!! Felipe