[![Shifted layer 2][1]][1]
(source: all3dp.com)
Your printer is skipping steps in the y-direction. This can have several causes. Take a look into Shifted layer guide on RapRap.org which lists 29 possible problems that can cause this issue and how to fix them.
First items of the list:
- Driver current is too low
- Driver current is too high
- Belt too Loose
- Belt too Tight
- Loose Set Screw/Grub Screw
- Belt or Bearing is binding
- Speeds are too high
- Acceleration is too high
- ...
When I was dealing with this issue on my RepRap I had to increase current to the particular driver. [1]: https://i.sstatic.net/fWRUk.png