Material Instance Parameter not saved

mmmh it seem like a bug to me …

i created a big master material i used multiple of material functions, and I copied it to create the color, roughness etc… each time I renamed the parameter but it seemed it kept some link to it …

problem2

if I replace a parameter with a new one it work, but now I need almost to replace every parameter with a new one …

or is there something can I do to break the link ?

thank for your help.