VFX Graph particleId issue

So I am trying to create a uniform 2d grid of particles with VFX graph. I simply compute some X & Y coordinates based on the particleId attribute of each particle and the size of the grid :

 int x = particleId % gridWidth;
 int y = particleId  /  gridWidth;

Here is the graph I use to do so : It produces the expected result for grids of size less or equal than 64*64. However, as soon as the size of the grid exceeds 64, the grid is flickering and some points are randomly missing at each frame :

I have no clue of what's going on, can anyone help ? what am I doing wrong here?