Color to alpha tool makes washed out colors

GIMP version: 2.10.2

Operating System: Linux

Package: Arch Linux package from official repo

Description of the bug

Color to alpha tool usage results in washed out colors.

I along with other people use a certain workflow to remove image backgrounds. It rests on using the color to alpha tool to turn the background transparent, along with making another layer, where the color turned to alpha is used to return full color to parts of the image.

The thought: full color image -> color to alpha white (removes white from image) -> add a white layer under the image -> white is returned to image and color should match original.

This is how GIMP 2.8 worked, however this is how it looks in 2.10.2

Reproduction

Is the bug reproducible? Always

To reiterate above stated.

Reproduction steps:

1. Open any image
2. Use the color to alpha tool to remove white from image
3. Add a white layer and place it under the now transparent image

…

Expected result: The coloring will match original image

Actual result: The color is washed out