Custom armor material has no color in item form, but its model does

[20008035]

Versions (Be specific, do not write "latest"):

Minecraft: 1.12.2
Forge: 14.23.5.2859
Mantle: 1.3.3.55
B.A.SE: 3.14.0
CraftTweaker2: 4.1.20.679
ContentTweaker: 4.10.0
Tinkers Construct: 2.13.0.183
Construct's Armory: 1.2.5.10

Observed Behavior:

Adding a custom material with a set color value has the default white color instead of the specified one.

Expected Behavior:

Parts crafted from the material should be the color set.

Steps to Reproduce:

Create script, as following:
#modloaded conarm

import mods.contenttweaker.conarm.ExtendedMaterialBuilder as materialBuilder;
//Adding Leather as a material
val leather = materialBuilder.create("leather");
leather.color = 0xc65c35;
leather.craftable = true;
leather.addItem(minecraft:leather);
leather.addItem(minecraft:rabbit_hide, 1, 36);
leather.representativeItem = (minecraft:leather);
leather.addCoreMaterialStats(4, 7.5f);
leather.addPlatesMaterialStats(0.9f, 0, 0);
leather.addTrimMaterialStats(1.5f);
leather.itemLocalizer = function(thisMaterial, itemName){return "Leather " + itemName;};
leather.localizedName = "Leather";
leather.register();

Load Minecraft, create a Leather Chestplate Core, and behold its uncolored beauty.

When I was trying to add color to this at one point, I tried making a resource pack, and after adding it in to make sure it worked (it had no content to it, it was just an empty assets folder and a pack.mcmeta), the parts had their color. Everything else works, the armor is functional and craftable, and has color when worn on the body, I just wish it had color in the inventory without having to make an empty resource pack and load it every time I want to play. Any help would be appreciated!