How to do a twinkling or shimmering effect on top of the butterfly effect

[xmaspixel_noob]

I'd like to do a twinkling effect where one white led will twinkle here and there throughout my model on top of my butterfly effect but when I use effects available on xlights that do this, I get 3 consecutive leds lighting up instead of just one. I'm able to get the twinkling effect but with 3 LEDs and it doesn't look good. How do I get it to light up only 1?

[Gilrock]

I'd just use the Sparkles slider.

[xmaspixel_noob]

Does the same thing, lights up 3 leds instead of just one

[Gilrock]

You're gonna need to give us more than just a description.