Arduino Mega + xLights

Hello, im trying to get simple sencuence file of xLights loaded from an SD Card, i followed this tutorial:

I did a bid of changes on my code, just related to the SD to work, and it does, but there's just a thing, no matter what i do, my LED strips doesn't do what the secuencer have on the timeline, for example:

This is what i have, just a plain blue lights

I just have the first 36 LED on the model
But this is what the LEDs do on real life (WARNING EXTREME FLICKERING LIGHTS):

I have been trying random stuff but complete out of luck and out of ideas, so if anybody with more experience have any clue what could be happening, or maybe a better way to to the same thing? anyway thanks a lot in advance

ps: led strips are ws2812b 5v