I have 120 leds strip controlled by nodemcu. Everithing works pretty well except one thing. When I turn off wled all leds swiches off but few hours later 5 leds at the middle of the strip turn with white color. Wled remains turned off in web interface. Has anyone faced such issue?
Welcome! 
I have not heard of that before, WLED completely stops sending data to the LEDS after turning off.
What I suspect is that either the first LED before or the first one of the ones that light up is slightly damaged and sends a spurious signal to the following LEDs due to electromagnetic interference or something.
You could add a relay hooked up to pin D6 of the nodemcu for cutting the power to the LEDs when they are off.
Did you ever resolve this issue. I have exactly the same problem with 2 of my strings.
I got the same issue on my latest led strip.
The nodemcu is about 1,5m cable wise from the strip and that is my initial thought on what is causing the problem.
Im waiting on a Dig-Quad for this installation and hope it will take care of the problem.
No, I tried few other software and just can say it’s hardware issue for sure. I moved strip a bit far from power wires and now it occurs only for one led. So I left it as is for now.
Sorry for delay, misssed notification.
What I’ve discovered is that WS2812b’s are very sensitive to noise.
As an example if you connect them to 5v without a controller and add a very short data line (say several inches) , over time various pixels will light up in random colours. It’s nothing more than induced noise through the data line, which is basically acting as an antenna. Using a screened data line to earth may fix the issue in noisy environments however a line level booster and 330 ohm resistor have always worked for me once the controller is powered up. I’ve had data runs to the first pixel of up to 12m with no issues of random pixels lighting or flicker.
Hi Modelman,
I’ve just build an another wled lamp, and i face this issue (few first led turns on when wled is off) for the very first time (much more distance between the strip and the esp).
I will give a try to a level shifter as i’ve got somes laying around.
About the resistor you mention, do you use it as a pull up at the input of the level shifter?
Resistor goes on the output of the level shifter before the first pixel.
i think it’s because the way you connect relay. if the circuit is power–led strip–relay–gnd, then when relay is turned off, power is still connect to led, together with control pin may cause some unexpected behavior. but if the circuit is power–relay–ledstrip–gnd, once relya is off, the power disconnect, then everything goes well.