Tech Knight belt Interior.

[killigraphy]

The interior color cannot be changed. Stays white/back.

[GM Korvin]

I believe this falls under similar issues as some other costume parts, though in the meantime there is a workaround: locking the colour theme across all different pieces, and then unlocking it to alter the others.

[srmalloy]

The Circle of Thorns shoulder piece that has the high collar and the capelet in back has the same problem; the only way to color the inside of the capelet is to link colors, change the colors globally to what you want the inside to be, then unlink colors and go around the rest of the character putting the colors back the way you had them.