Single leds are flickering on above 130 brightness

Hello,
my setup is 399pcs WS2815 leds
PSU is 150W, 12500mA limit, LED voltage 12mA (WS2815)
ESP32 with ABC! WLED v63 board
WLED v0.14 creative

Everything seems to be working good, but when I put brightness above 130, with LED effects i do see random single leds flickering (like power cuts for miliseconds). Defect is not visible for max brightness solid colour effect.

Asking for community for advise, thank you!