There is a bug related to wires and switch stations

[VinAdmin]

The lamp remains lit when two switching stations are on the same network.

I remove one switching station and the lamp goes out with the network broken.

[SmallJoker]

Adding and removing the switching station may break the entire network until they're all remove and re-added. Here's a minimal world to reproduce. However, I cannot reproduce your disconnected light case.
flat_technic.tar.gz

[SmallJoker]

@VinAdmin Would you please be so nice to check whether this diff solves this issue? changes.diff.tar.gz

I found that the technic machines do turn off automatically after a timeout of 2 seconds. This is done by the ABM called "Machines: timeout check". Hence the lamp will turn off eventually (unless clear_networks failed to complete its job).