Hi
Y motor runs normally then slows at some point during print at Y home direction then goes at normal speed when prints in opposite direction. I marked with red at second cube image pattern where Y motor slows. This cause to have rectangle base shape instead of square. More wired result was during printing circular objects, the are not even ellipse but something like cat eye shape?
Belts are tighten well. I have Menzel board on Huxley Revision 2013-05-16

Any idea what is causing this and how to fix it???