They seem to have a very, very dim glow when operating, which oscillates a bit and is only noticeable when zoomed out. More than that though, they seem to be overlaid on top of a black square, like the floor under them has been replaced with vantablack.

I suspect some manner of mod interaction on my end and I'll try disabling some things to see if I can pin it down.

Actually, I can confirm that it happens with only K2SO, Disco Science, and Editor Extensions to let me quickly test it. In fact, while the Krastorio Advanced Lab is the only one that has a black background, they all seem kind of weird? It's like the colors aren't applying, and so the labs sort of stick to one color and flicker in brightness.

I took a screenshot of it and hosted it on imgur here: https://imgur.com/a/8nsgRwd

I'm running on Linux, and so I've tried a couple different renderers and toggling all the graphical settings I can find. I've also tried disabling the Sprite Atlas Cache from the hidden settings in case that was an issue. None of it seems to have changed things.