I had this problem before but assumed it was just a problem with my coding so I restarted my project and it's still happening so I ask, why does a blocks texture while in the player's inventory use another blocks texture?

 

The block that's using another blocks texture

Registeration

public static Block ChanceBlock;
ChanceBlock = new ChanceBlock(Material.cloth);
GameRegistry.registerBlock(ChanceBlock, "ChanceBlock");
registerRender(ChanceBlock);
Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register(item, 0, new ModelResourceLocation("avon:ChanceBlock", "inventory"));

All the methods the above code are in is called in the init().

Blockstate.json

{
    "variants": {
        "normal": { "model": "avon:ChanceBlock" }
    }
}

Blockmodel.json

{
    "parent": "block/cube_all",
    "textures": {
        "all": "avon:blocks/ChanceBlock"
    }
}

Itemmodel.json

{
    "parent": "avon:block/ChanceBlock",
    "display": {
        "thirdperson": {
            "rotation": [ 10, -45, 170 ],
            "translation": [ 0, 1.5, -2.75 ],
            "scale": [ 0.375, 0.375, 0.375 ]
        }
    }
}

 

The block that the texture is being taken from

Registration

public static BlockOre XeserOre;
XeserOre = new XeserOre(Material.rock);
GameRegistry.registerBlock(XeserOre, "XeserOre");
registerRender(XeserOre);
Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register(item, 0, new ModelResourceLocation("avon:XeserOre", "inventory"));

Again, all called in init();

Blockstate.json

{
    "variants": {
        "normal": { "model": "avon:XeserOre" }
    }
}

Blockmodel.json

{
    "parent": "block/cube_all",
    "textures": {
        "all": "avon:blocks/XeserOre"
    }
}

Itemmodel.json

{
    "parent": "avon:block/XeserOre",
    "display": {
        "thirdperson": {
            "rotation": [ 10, -45, 170 ],
            "translation": [ 0, 1.5, -2.75 ],
            "scale": [ 0.375, 0.375, 0.375 ]
        }
    }
}

 

If you need any more code to help me, I'd gladly get it to you as soon as I can.

Thanks

  ~Macncheezy

What does your registerRender() Methode ?

Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register(item, 0, new ModelResourceLocation("avon:ChanceBlock", "inventory"));

 

I think you should be using the 'getItemFromBlock' method from the Item class as the first argument in the .register function.

 

Maybe try

Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register(Item.getItemFromBlock(ChanceBlock), 0, new ModelResourceLocation("avon:ChanceBlock", "inventory"));

 

Also, you should camelCase your variables instead of TitleCase.  It's a little confusing to read.