I remember reporting on this. It started when the game moved from 0.8.6.0 —> 0.8.7.0
Unfortunately, it’s not just smooth dirt. Most outdoor areas (including smooth autumn) have been permeated by a blue-ness in the dark. Here’s a rough building I made in the pitchest black setting
And largely unedited area from Resort where it bleeds in.
And I’m pretty sure it’s almost game-wide. I do not remember the plaza being this blue a year ago.
In fact, I was looking through old screenshots and footage and found how normal it looked during Halloween (0.8.4.0).
I am certain this also started from the 0.8.7.0 update.