They do change color but the above photo is a couple of years after installation -original color is lighter and more of a reddish yellow -this is red cedar, white cedar weathers differently and other shingles can be pre-dipped or stained to maintain a specific color -these are natural, reference a similar question with an earlier photo of the shingles:

[https://www.houzz.com/discussions/what-type-and-color-is-the-shingle-on-the-house-and-does-it-weather-or-remain-that-same-color-thanks-dsvw-vd~518648[(https://www.houzz.com/discussions/what-type-and-color-is-the-shingle-on-the-house-and-does-it-weather-or-remain-that-same-color-thanks-dsvw-vd~518648)

Below is a more recent photo from our website of this house from last year (10 years after original installation):

https://thorsonrestoration.com/portfolio/plymouth-summer-retreat/#&gid=1&pid=1

Thank you!