XYZ cube problems - hard lines above and below X?  

XYZ cube problems - hard lines above and below X?

Finished building the prusa mk3 a couple days ago, and things look mostly good, but there have been a few issues here and there. A slight layer shift on my triceratops skull, some wobbly texture at the top of me shopping bag handle, and weird bumps up and down the rounded corners of my soap holder.

But the line on this xyz cube is the worst that I've seen so far.

https://www.imgur.com/a/7W1zO2N

I was printing this bag handle this afternoon and think I had some wobble when it got past the halfway point up there. I put a 5mm brim on it, so adhesion was no issue, but since it's a relatively skinny part, sticking off the bed at a 45 angle, I assume there is much more potential for that.

Belt status:
X: 274
Y: 270

Y distance from min:
Left: 11.32mm
Right: 11.37mm

Measured Skew: 0.02

[0;0] point offset:
X: 0.08mm
Y: 0.82mm

Any ideas what is going on here?