This has likely been reported before, but I'll post this anyway just in case.
This is true even close to the center, but gets extremely noticeable far away (go to around 50 | BQ for a noticeable example).
The glow effect that surrounds the cursor when zoomed out seems to be only able to exist at certain locations. Zooming in and out this far from the center results in the glow going haywire.
Judging by the circumstances, this is almost certainly is a result of floating-point imprecision. I'm not actually sure how this could be solved to be honest, maybe keeping the camera centered and moving the world around instead?