Last Layer not fully printing & Zig Zaging on Y axis

I have been trying to solve this issue since I received this printer and cannot get a single finished part because the last layer will not finish. Has anyone else dealt with this or know how to fix it? Below is everything I have already tried.

I set the top layer to 100% on the advanced print settings
Tried 120% on the advanced print settings
Tried Rectilinear and concentric for the top/bottom fill pattern
Tried Repetier Host V0.85b and also V0.90C
Different models (simple and complex)
New models

I'm also getting those zig zags on the cubes and on different shaped objects even after checking the "Randomize starting points" checkbox on the print settings in layers and perimeters.

Any help or advice is really appreciated. Thanks

 

Ali, I don't have real solution but want to let you know you are not the only one seeing this. I believe that if you place/print more than one of the same objects (or at least objects with the same number of layers) as one job, only the final object will be affected. If that's not the case for you then we are experiencing different problems.

I'm very new to this, and haven't had time to research it yet, but am wondering if it's possible that the Gcode is somehow getting truncated....

 

Thank you for the post, I will try to add two parts to see if it will finish the second. I appreciate the help.