Problem with grid infill (line positioning)
It looks like a case of one axis affecting the other.  This is a subset of cases where things are not rigid enough.  Basically the movement direction in X is causing an offset in the Y, or whatever you want to call the axes.  It is present in small amounts in all screw-driven setups where the screw essentially acts as a wedge, and can be in others for various other reasons.  The solution is to tighten up your linear bearings/slides so that there is less transverse play.
There is also a chance that you are trying to print beyond the resolution of your printer, in which case it is &quot;rounding&quot; to the nearest within its capabilities, but that seems less likely.