Probably due to the invisible entity following you around, which is weird because it has no collision. To replicate, move one or two tiles to the side from a substation and try to move and drag-place them. No idea if this happens with other mods that utilize the same workaround and pretty sure it's not fixable, still wanted to let you know.

That's strange. After playing around with it I think that it's that it's trying to place the substations to cover the invisible lightning rod within the electric network. This behavior seems to only happen if the player's position is inside the supply area. While the lightning rod does not interact with the electric network, it does still enter it; I don't really know how to prevent that from happening.