My arm has a mix of grey and black when I turn invisible?

Hello, I was making an invisibility tool to test it out with Armor. Turns out, all of the Armors sort of
created an extra layer of grey when I become visible. If someone can help, I would be very much grateful.

EDIT: I think it's because a part welded in the arm, but not sure

https://gyazo.com/aef98101f8e177644cdebe6e6b3ae33a

local Tool = script.Parent
local Equipped = false
Tool.Equipped:Connect(function()
    Equipped = true
    for _,part in pairs(workspace.SurfyStefanos:GetDescendants()) do
        if part:IsA'BasePart' and part.Name ~= "HumanoidRootPart" then
            spawn(function()
                for i = 0,1.01,.1 do
                    if Equipped == false then
                    end
                    wait(.02)
                    part.Transparency = 1
                end
            end)
        elseif part:IsA("Decal") and part.Parent.Name == "Head" then
            spawn(function()
                    if Equipped == false then
                    end
                    wait(.02)
                    part.Transparency = 1
                end)
        end
    end
end)
Tool.Unequipped:Connect(function()
    Equipped = false
    for _,part in pairs(Tool.Parent.Parent.Character:GetDescendants()) do
        if part:IsA'BasePart' and part.Name ~= "HumanoidRootPart" then
            spawn(function()
                for i = 1,0,-0.1 do
                    if Equipped == true then
                        break
                    end
                    wait(.02)
                    part.Transparency = 0
                end
                return
            end)
        elseif part:IsA("Decal") and part.Parent.Name == "Head" then
            spawn(function()
                for i = 1,0,-0.1 do
                    if Equipped == true then
                        break
                    end
                    wait(.02)
                    part.Transparency = 0
                end
                return
            end)
        end
    end
end)