Working on iPad Pro (iPadOS 15.2), App version 7.1.1 at time of post.
Problem: Manual coloring option in any mask does not display the existing setting from previous edits (it stays at the unset state, no color, Saturation: 0).
Steps to reproduce:
1. Edit in any mask, set any manual color in the "Color" panel, saturation > 0 (for disambiguity, Color setting in this case refers to the last option in the "Color" panel)
2. Exit mask editing by clicking "Done". The manual color will display on image as desired.
3. Enter the same mask edit, the manual color will still be correctly displayed on image, but under "Color" panel, Color setting is displayed as unset.