Ahoy there sparkies!

[Trogladyte]

I have a conundrum.

In the hall downstairs there are two lights that operate together, controlled by two switches, at opposite ends of the hall. Its a pretty standard setup. The bulb at the kitchen end blew, and i kept forgetting to fix it. And then I noticed hat the bulb at the front door end would not switch off completely. Switched on it is bright, but switched off it is dim. If I replace the blown bulb with a 15w LED this behaviour continues - switch on, and both lights on. Switch off and the kitchen end goes off, and the front door end goes dim. If I replace the bulb at the kitchen end with an incandescent, it all works normally.

The only thing that is noticeably different to standard that i can see is the switch at the kitchen end, which is a light sensitive thing that can be set t turn the lights on at night when you are on your hold, but it is switched to normal operation, and I cant see how that could cause this effect.

Thoughts?

[Horse]

Your house is haunted. Move immediately?

[Wreckless Rat]

Take off and nuke the entire area, it's the only way to be sure...

[KungFooBob]

Sounds like an Earth Leak, the Earth is leaking the souls of the dead into your house.

[Skub]

Shoggoths in the wiring.

[Yorick]

Same here on lower staircase . All 3 lights emit a light glow which is just enough to see by at night

Our sparky explained it away.

[Mussels]

I've had this occasionally, I suspect it's lights that use transformers. Because a transformer is still connected to neutral when switched off it still gets a sine wave on one side which is possibly enough to produce a small current.
I've never looked into this properly so it's a guess.

[crust]

My guess would be the photoswitch in the kitchen.

It's most likely a semi-conductor switch so will not mechanically break the circuit like a normal on/off switch.