Error in particle inspection and void fraction calculation

I have faced a problem in particle inspection and void fraction calculation by CFD side, which I think might be a bug.
When, I insert a particle in the middle of my domain, (100*100*160 mm cube) only a quarter of the particle has been identified by the CFD. On the other hand when I move the center of the particle from p1=(50,50,120) to a bit to the corner to p2=(30,30,120), the whole particle becomes visible.
As it can be seen also in the attached figures the values of the void fraction makes it clear as well that when particle is in the center the whole volume of the particle is only assigned to a quarter of cells.
For the void fraction I used BigParticle with scale up volume of five, the diameter of the particle is 15 mm and the cell size is 2*2*2 mm.

The code by which I insert the particle in Liggghts is as follows:

# particle insertion
#======================================

create_atoms 1 single 0.050 0.050 0.12 units box
set atom 1 diameter 0.015 density 1120 vx 0 vy 0 vz 0

#======================================

Thanks for your time