WS2811 lights

Other Hardware LEDs and Multiplexing
9

you have got the leds initialize twice, once is ws2811 and then, again, as ws2812 (neopixel).

you need to comment out

FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);

so that it is

// FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);