Sometimes on survival worlds, random particles appear in random places and stay there. Some examples I have seen include: Smoke particles appearing 5 blocks off of the ground
The particles that would normally appear when breaking a dirt block, In the shape of a dirt block, in the altdim5.

Mods I have: Immersive Portals, OptiFabric, Pehkui

Speaking of those particals that would normally appear when you break dirt, I just got on my survival world again and there are more of them. I think I can send a screenshot.

I'm going to close this issue and open a new one that contains what I suspect is actually happening, because some new info has come to light