There is a positional overlap between Planet Paracelsin 1.2.2 and Nexus Extended Promethium Endgame (WIP) 0.9.7.
In-game screenshot.
Something like Cosmic Social Distancing fixes this externally (which is the point of that mod to be fair), but unless I'm missing something I don't see why that would be necessary. I'm only reporting to you because Nexus was made first, so in my brain "they have that spot" but as Nexus is missing from the Enable All Planet Mods mod, I wouldn't be surprised if it just went under the radar as a spot that was already being used.
Maybe both mods want that spot in space because it has certain connections/sun distance? Either way, the mods aren't directly compatible right now so I thought I'd report it, if this is something that would be better fixed on Nexus' end I can head their way as well, but as I said based off of creation date alone I'm reporting to you, not an expert modder so I'm not sure, I just report bugs lol.