Open the "black box" - to understand the wires going to the chandelier?

Question

Do it yourself

Hello!
I climbed home to change the chandelier, and realized that I don’t understand something in this life. Stumbled upon some crazy situation.
In more detail, we have:
- Double switch
- Mounting box, tightly closed with wallpaper (black box)
- 4 wires going to the chandelier.
What strained - a screwdriver to search for hidden wiring rang on all 4 wires, regardless of the position of the switches.
I took a voltmeter, attracted my wife as a remote switch and recorder of readings. Sequentially went through all 4 positions of 2 switches and measured the voltage between all the wires.
This resulted in the following table:

I looked at the plate and found that there is not a single combination of wires in which the voltage would be zero with the switch off, and 220 with it on. Before that, a chandelier with housekeepers hung and worked, it seems, due to the fact that at 120 volts they do not light up . I don’t know what this mode of operation threatens the housekeeper with.
I am not new to working with 220, but something interfacial happened here. Maybe someone has an idea how this can happen and what can be done about it in the short term? At the weekend there will be guests and arrange an autopsy of wallpaper and replacement of wiring - not an option.

Answer 1

but you don’t measure with a voltmeter - take two lamps, connect them to one contact and try to connect them in different combinations. You will not cause damage with any connection - voltages greater than 220 will not fall on the lamps, you will not burn the wiring in any combination. The voltmeter has a high input resistance - it can measure induced potentials.

Answer 2

Your switch seems to break zero and not phase.
Here it is better to specifically understand the wiring - even at the cost of wallpaper.

Answer 3

the housekeeper has an extremely non-linear characteristic - in the extinguished state it has a very high resistance, determined only by the leakage currents of the ballast. in a conventional gas-discharge lamp, in the extinguished state, the resistance is generally infinite.
ps answered in the wrong place, sorry

Answer 4

Tell me, what kind of device is a “screwdriver for finding hidden wiring”?