Some who has encountered the same bug on Capnbubs helmets posted this on another forum:
"Hey there,

Not sure if you're still having this problem, but I had the same...I manually deleted the mod folder from the steam workshop location, unsubscribed then re-subscribed the mod for a fresh download, and it seems to be fine now."

This is from another game, but maybe could be of help: "If you're seeing the textures of the game appearing black on your screen, please ensure that NVIDIA's Anti-Aliasing controls are disabled in the NVIDIA Cotnrol Panel"

Please, fix your mod. On screenshots your suit looks excellent. I want to dress all of my operatives in this ARMOR!

This is my mod list:
A Better ADVENT
A Better ADVENT: All The Enemies!
Long War SMG Pack
Long War Leader Pack
Muton Centurion Alien Pack
Long War Laser Pack
Long War Perk Pack
Grimy's Loot Mod
Mod Everything
Grimy's Bruiser Class
Grimy's Headhunter Class
Gotcha (Flank Preview Evolved)
True Concealment
Evac All
Capnbubs Accessories Pack
Military Camouflage Patterns
True retroactive AWC
Overwatch All/Others
XCom International Voices Pack
More Maps Pack
Star Wars Helmets
World Expansion Project: ADVENT
Tech Tree
Lucubrations Infantry Class
Show Enemies on Mission Planning
Additional Icons
Additional Mission Types
Mod Config Menu
Blackmarket Usage
Cost Based Ability Colors
Maps by Vozati
LW Samurai Class
Katana Pack Reloaded
Japanese Voice Pack
ADVENT MEC : Breacher
Soldier Fatigue Updated
Mercenary Plasma Weapons
Rogue Class Mod
Smart Overwatch
TheAxeMod
Elite Viper
Perfect Information
XXL Tattoo Pack
Uniforms Manager

Just for info I've had the black textures bug when I've renamed the .XComMod file (had it with Capnbubs mod, but that was downloaded from Nexus. Not sure how many Workshop users would rename that file). Very odd.

Thnx for the Info; it must be something minor like that, cause only a couple users reported that on both this and my other mod. Must be something individual.

Verifying the game cache might just work for people with this black texture bug. Just a suggestion.

Yeah, i did suggest that also, so far only 2 ppl reported that. don't really know where that's coming from...

Doesn't work for me. Got pure black armor when I tried the mod.

found this around; don't know if this could be of any help: https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=683218526

Also; any chance you guys are playing on Mac? I had another user on Mac having the same problem with the helmets.

Windows 7. Getting the black texture bug. Here's my current mod list as requested:
https://steamhost.cn/steamcommunity_com/profiles/76561198018606604/myworkshopfiles/?section=collections

This is bug ONLY in THIS MOD! All others mods works fine together. But only one, this mod not worked. Yes, this is armor looks like awesome gear, but author need add more compatibility to his mod.

Just tried an hotfix and reuploaded; let me know if that fixed anything.
thnx

Still getting black armor for this mod.

getting black texture, too