Hello,
This has to do with the default pixelDensity() for each device:
https://p5js.org/reference/#/p5/pixelDensity
https://p5js.org/reference/#/p5/pixels
I get the same results as you do on the same device with this (one of them) added to setup() :
pixelDensity(1); //Shows 1 fractal
pixelDensity(2); //Shows 2 fractals
I first came across this issue with this example and had to set it:
:)