Sooo, it's been a problem for a very long time, and I haven't seen anyone addressing it in the forums.
I have a character preset that I set to have "blonde" hair. The problem is that it keeps reseting to "dark grey" over and over again after a game is finished.
I think no one noticed because "blonde" is actually deep brown, "dark grey" is actually black, and pretty much every single hair colour is just a different shade of black anyway.
Not only this bug has to be fixed, the hair colours have to be fixed too ! Blonde should be blonde, not deep brown !
The actual hair/facial hair assets already are low-detailed and look like wigs and fake beards/mustaches, so they at least should be the right colour and should keep being the colour you set it to be.