[gmx-users] Shifting in minimization

[Alex]

Dear all,
I have system containing a solid slab and water molecules on top of it in a
rectangle box (   6.67350 , 6.96840, 8.68584). I do not know why the whole
slab completely shift in the Y direction after minimization!? The shift
approximately is equal to the Y-cell size (6.96840). It might not be
critical issue due to presence of PBC, but at least is weird and not good
looking. The pressures in XX, YY are similar in my knowledge. Would you
please let me know I can find the reason and how to fix it?
Thank you
Alex