Unlinking a color to setting

Linking is a Library operation. Somewhere, when you were editing your Library and Cut/Layers, you linked that layer to one of your Library entries. Open your library tab and find out which setting has been linked.

Select the Layer and under the cuts/layers window it shows the link from your library and it should also show an Unlink button. Press that and you’re done.

You may need to save your Library after unlinking.