Pipe organ effect

I don't know if this just has to do with me using the default FluidR3 soundfont or if it happens in all soundfonts but I get like a pipe organ effect when I have the flute doubled by the piccolo and both in their high registers. It almost sounds like I have an organ playing until one of the instruments lowers their register, at which point I can recognise it as flute and piccolo being doubled because it has a flute-like timbre.

But why am I getting this pipe organ effect in musescore? Does it have to do with me using the default soundfont that comes with the software?