Since it appears only to be in a single corner, that actually looks like a CAD or slicer issue to me.
I had a similar sort of thing happen when I was becoming accustomed to the relative weirdness of TurboCAD (I am a long, long time user of Inventor at work so TurboCAD can be rather alien to me in the way it does certain things).
If the solid model meshes do not connect properly, or are misinterpreted by the slicer that sort of thing can happen.
It could also be that the slicer is using the same "start" point for each layer and doing a retraction or pause or other such thing at that point.
Or it could be speeding up with increasing layer height.
I don't know, but you might try a solid cube (with maybe 20% infill) instead to see what happens.
I suppose it could be some odd issue with motion or temperature, but that would not be my first guess because everything else looks so good.