Fairings do not have textures or are transparent, they have only shadows.
SC-GEN-FR, SC-GEN-FR-W
KSP 1.8.1

Not sure if you've already dealt with it, or if this is even the issue causing it, but in case it is.

Both SC-GEN-FR-N, and SC-GEN-FR-W have "TextureURL = SSTU/Assets/SC-GEN-Fairing-DIFF", which doesn't appear to exist in the assets folder. The closest being SC-GEN-FR-DIFF.dds

Was just about to try a quick MM patch to see if that fixed things, if my computer doesn't explode I will let you know if it works or not.

Having it look for SC-GEN-FR-DIFF instead of SC-GEN-Fairing-DIFF seems to have fixed the problem.

@Repseki Since this has not been fixed yet, do you still have that fix for me??
All my beautiful painted SSTU rockets are currently being ruined by ugly stock fairings...