From the pictures, you can see that besides the offset, the layers are all looking good, so the stepper motor seems quite innocent. It is also rather unlikely that your slicer randomly adds a few millimeters to the X or Y coordinate.
Since the layers above the offset are also moved a few millimeters and not microns, most definitely a belt skip. It is also unlikely that someone bumped into the printer so hard that caused a belt skip. Why this belt skipped happened could be caused by belts that are wrongly tensioned or one of the teeth is damaged. I would put my money on:
Are the belts too loose or too tight?
Does the top and bottom part of the belt have equal tension on each axis?
Examine all the teeth of the belts to ensure they are not damaged
Examine all the teeth of the gears driving the belt to ensure they are not damaged
The offset shows that there is a problem on one axis only. So just check the axis parallel to the direction of offset, the problem should be there. If you cannot find anything I would let someone more experienced examine it or contact Flashforge.
