WC should have 2 traits (undead and fearless).

If not they would either get fearless or undead...

data/units/Undead_Corpse_Walking.cfg

@@ -6,6 +6,7 @@ race=undead
 image="units/undead/{BASE_IMAGE}.png"
 {MAGENTA_IS_THE_TEAM_COLOR}
 ellipse="misc/ellipse-nozoc"
+num_traits=2
 {TRAIT_FEARLESS}
 hitpoints={HP}
 movement_type={MOVETYPE}