LED turning on with disconnected controller

Hi,

after I set up my first WLED project, I noticed a few hours later that the first LEDs of the strip turned on.

At first, I thought it might be a wrong setting in WLED. But no… In WLED, it shows that the strip is turned off. So, I completely disconnected the controller. And after a few minutes, the first LEDs lit up again.

I use the following Hardware:

And an ESP 8266, which I can´t link here, as I am a new user

I connected the power supply directly to the strip. The ESP is connected with the data cable and the ground. Where are these instructions for the strip coming from, and above all, how can I fix this? Is the power supply the cause of the issues?

In LED Preferences check the box that says ‘Off Refresh’. You are experiencing noise on your data line.