Flashes at end of static patterns

I’m seeing flashes that are kind of random but not totally. It looks like in some cases a “+1 pixel” gets activated.

  • Timing seems random
  • Color seems to be the color of the previous pixel
  • Looks like only one pixel flashes on one pin at the same time (if multiple pixel flash at the same time, then they are on different pins)
  • Best seen at edges between light and dark areas
  • Best seen with static patterns

Here is one taken from a slowmo video:

I’m using

  • esp32 dev kit
  • around 3.000 LEDs
  • 6 pins - each of them powering one column
  • 200w power supply with multiple power injections
  • logic level shifter for each of the 6 strips/pins
  • 40 LEDs are grouped for each square

I’m seeing this effect with wled 0.14-b1 and 0.14-b4.

Do you have any ideas what could be the reason?

And in real-time here: https://youtube.com/shorts/EzbGr8oMLJ8