Redstone Contraption working only on the z coordinates

I Build a contraption to push the iceblock forward after it is pulled back by the slime block.

The z coordinate is -900
the x coordinates are irrelevant
But event at -899 z coordinate the contraption doesn't work as it should.

These are identical Builds but other coordinates i made a Video to show it:
https://www.youtube.com/watch?v=mgRrroOvpWU&feature=youtu.be