When I build a transformer and remove it, there will be two lamps left on the ground that cannot be removed, but they can be powered by putting up a pole.

I think you probably are using a lighted-electric-poles mod. I'm not sure I can really fix that on my end.

ok, thx for answer ill try without this mod. :)

I have a related issue in blueprint sandbox. When copying, cutting or using alt+d, an invisible input and output stay or get copied as well. this does not happen on nauvis fortunately. this mainly happens when the wires are connected to the transformer.
the invisible input and output cannot be removed in the sandbox but if i copy or blueprint from there and paste into nauvis, i can remove the invisible input and output.
I am playing with many other mods but none that modify power like this mod.
This is likely an issue with Blueprint sandbox as it also crashes when upgrading a miniloader redux. I thought i would post here first as this can get very annoying when faffing about with designs