>>44900
>How long the light illuminated? Or is it constantly working?

Constantly. Technically wall switch must completely break circuit, and I think it does. But there still a current, and less than 220. Like it flows through something around wiring (but without short circuiting, otherwise electricity must switch off automatically).

>I've seen a led bulb very slowly going dark after switching it off (not sure how long it took tho).

These bulbs didn't do this for year, so it isn't bulb-specific.

>If you are lucky. Sometimes they just smear the plaster over the wiring.

I don't even know where are the wires, except on some places where switch is located. It is typical USSR-style wiring, two systems, "top" for ceiling lights, "bottom" for wall sockets. Ceiling ones may go in tubes inside concrete plates, or may be between the plates in plaster. Anyway, last thing I want is replacing everything right now, it is too destructive and time consuming.

I can disable them at board, not for specific room, but for all flat. "Bottom" is ok, otherwise it would be catastrophe, but having no "top" is also not so fun, considering that some rooms have only "top" lighting. "Top" is also ok everywhere except that room.

I has no time to test anything with multimeter today (because work), so now there are only theories.