Failed to load mods: flib/data-util.lua:18: attempt to index local 'prototype' (a nil value)
stack traceback:
flib/data-util.lua:18: in function 'copy_prototype'
...objects__/scripts/prototypes/fulguran-ruin-attractor.lua:137: in main chunk
[C]: in function 'require'
use-fulguran-objects/data.lua:8: in main chunk

Do you use a mod that offers new types of electric poles or changes behavior of existing poles? If yes – which mod is it?

It looks like that there is a pole without recipe.

most likely, more than one, the subsurface one has independant power poles used to build underground.

Bingo.

Adding this mod instantly triggers the fault.

At a first glance – the two entities tunnel-entrance-cable and tunnel-exit-cable do not have recipes. Must have a deeper look at it to fix that.

V 1.0.3 with the fix for this issue is online.