I don’t think this is unusual. I am sure we’ve had previous threads on more major components than bolts showing early superficial rust.
Our black 2012 Mazda 3 had similar rust on bolts like this when we got it couple of years ago. A quick thin coat of Hammerite and they have stayed free of visible rust. Our 2012 Civic had the odd slight trace too from about five years old but being blue I didn’t want the fiddle of doing a neat job with the black paint and just left them bare. I’ve just had a look under the bonnet on my 2018 Golf and there are only two of this type of bolt easily visible and one is showing very slight corrosion.

Each car lives on an open drive 70 miles from the sea.

In every case the bolts look galvanised but I am pretty sure they are not. Even so the rust just seems to remain on the surface and be cosmetic. The worst of my three examples is the old Mazda but they looked a long way from seizing or rusting badly through when I painted them.

I wonder if anyone on here has a Toyota as with their fastidious reputation I wonder if they might protect theirs in some way.