I found a patch of what appeared to be particulate matter sitting there near the space station in the starting system on a new save.

I flew closer, and it became apparent that it was something stranger - no designation, no sound effects, no interactive element. But permanent, even after loading and restarting the game.

It is comprised of numerous dots of light, sprites that grow suddenly in size when I fly close, to the point of filling my screen with light.

Of interest - the spots seem to vary in colour like the stars. And of particular interest, they all render BEHIND planets/stations/other large bodies.

I'm wondering if what I'm looking at is actually part of the skybox somehow; if what I'm seeing is the star field that projects onto the background, but... wrong. Visible when it shouldn't be.

Unsure. I think the GOG version is still at 3.97? It's at whatever the current live GOG version is.

I came across something like this, as well, while I was pulsing to a mission location in space. It was a while ago so i don't remember much. I think the mission bugged and I had to restart the game. (v3.96)

GoG has NMS 3.98 available on galaxy and the website for offline installers.

Yeah literally after I posted this, the game updated.

The anomalous... thing is still there.

Maybe it's one of this:

Enhanced Nebulae
New Asteroids
Asteroid harvesting encounters
Asteroid inhabitants
Space Storms

mentioned here:
https://www.nomanssky.com/endurance-update/

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