Q: Why did my rose bush produce 1 rose of a peach color while all the others are deep pinkish/reddish?
A: I can’t see where the peach blossom originates in the rose, but it is likely a “sport“.
These flower changes happen in many blooming shrubs, including camellia and azalea. It’s how some of the most famous varieties got their start.
If the branch that has this flower continues to grow vigorously, you could take cuttings and root them to make more shrubs with the same flower.