Just for kicks i downloaded your map, and put down a power pole, connected the red wire from light to pole and it had "Read Signal" checked (i.e. had been connected to circuit at some point), removed that and it works as it should.
Only thing that tells me is that the game isn't checking the circuit ...

And i of course forgot the mods and the savefile, here that is

Not sure if this is another bug or part of the same thing, but starting the server with a new map (which works) still leaves the .lock file in the factorio directory after server stops.

Tested creating a new map in 0.16.8 and that map runs fine, issue seems to be with loading the pre-16.8 map in 16.8 (16.7 map in this case)

factorio log only shows this

1.119 Custom inputs active: 0
1.121 Factorio initialised
1.122 Info ServerSynchronizer.cpp:29: nextHeartbeatSequenceNumber(0) initialized Synchronizer nextTickClosureTick(0).
1.122 Info ServerMultiplayerManager.cpp:696: mapTick(4294967295) changing state from(Ready ...

Set a pump to pump water if water > 0, occasionally it leaves 0.X water in the tank and the pumps stop pumping. This leads to a train set to "fluid count: Fluid = 0" staying in the station until i force the pumps to pump the last 0.1 to 0.9 out of it.

Suggestion for fix: Use Integer - either 0 or 1 ...