hair, clothing, shoes, etc colors/settings are often changed using a HUD provided by the creator in their "fatpacks". I have noticed very recently that color changes are not "saved" with a relog. In the past, color changes have consistently reverted back to their previous saved state if the viewer crashed. To prevent that from happening in the case of a crash, I will sometimes relog to "save changes made to my outfit".
However, I logged out last night & when I logged in this morning found that my hair color had been reverted back to its previously saved color, not the color I had selected last night. (I did not relog to "save") Oddly, other items in my 'fit had not reverted (shoes, necklace).
I have noticed this on one other occasion, but assumed it was a fluke at the time so did not report it.