I have three rooms in my basement that have all their ceiling light circuits wired up in sequence. They are all single switch circuits and the first two rooms have 4 ceiling lights each and the last (the bathroom) has two circuits in it. One switch controls two ceiling lights and the other controls a ceiling light and small exhaust fan.
All the ceiling lights are 15 watt recessed lights.
I have them all wired up the same as this diagram except move the second switch to a separate box and add two more circuits, plus more lights on each circuit. It's pretty basic wiring. Each switch has three wires going to each box, the first going to the lights, the second coming from the power source, with the third wire continuing to the next circuit. The neutral wires are all connected in each and the grounds are all connected.
This wiring diagram belongs to do-it-yourself-help.com. The original image can be found here: https://www.do-it-yourself-help.com/wiring_switches.html
I noticed two nights ago when my wife went to the bathroom when she turned on the bathroom light, all 4 ceiling lights in the bedroom showed a TINY amount of light and then subsequently dimmed! LED lights take a few seconds to turn off, slowly dimming in the process. It was quite noticeable, but you can only see it in the dark. It's not enough to get around in the dark though.
Is this normal? Do I have a problem with my wiring setup?? Do LEDs behave this way?
Edit - this morning I tested with a voltage sensor, and it does indeed beep for a split second when hold it up to the bedroom light wire while turning on the bathroom light. The same for every other circuit. This indicates a small bit of power goes through the wire. Is it traveling back through the entire neutral wire, even on the other circuits?