Is this long and/or hard braking? Or just even a small light squeeze to scrub off a little speed?
I think some noise is pretty normal with many bikes if you’re having to brake hard or long enough for a lot of heat to build up. If it stops pretty quickly as the heat dissipates then I don’t think it’s anything to worry about. Possibly can be solved with XTR or DA rotors, they’re supposed to be better under hard braking.