Why does the "part" in FindPartOnRayWithIgnoreList return nil?

This works in studio but not ingame, ingame "Part" returns nil. Part is defined as the object the ray has touched.

local remotes = game:GetService("ReplicatedStorage"):WaitForChild("Remotes")
local tool = script.Parent
local player = game:GetService("Players").LocalPlayer

local ignoreList = {player.Character, unpack(tool:GetChildren())}

tool.Equipped:connect(function(mouse)
    mouse.Icon = "rbxassetid://251138645"
    mouse.Button1Down:connect(function()
        local ray = Ray.new(tool.Handle.CFrame.p, (mouse.Hit.p - tool.Handle.CFrame.p).unit * 300)
        local part, position = workspace:FindPartOnRayWithIgnoreList(ray, ignoreList)

        local beam = Instance.new("Part")
        beam.BrickColor = BrickColor.new("Institutional white")
        beam.FormFactor = "Custom"
        beam.Material = Enum.Material.SmoothPlastic
        beam.Transparency = 0.25
        beam.Anchored = true
        beam.Locked = true
        beam.CanCollide = false

        local distance = (tool.Handle.CFrame.p - position).magnitude
        beam.Size = Vector3.new(0.3, 0.3, distance)
        beam.CFrame = CFrame.new(tool.Handle.CFrame.p, position) * CFrame.new(0, 0, -distance / 2)

        beam.Parent = workspace

        remotes['RayReplication']:FireServer(beam.Size, beam.BrickColor, beam.CFrame, beam.Material)

        table.insert(ignoreList, beam)

        delay(0.4, function()
            table.remove(ignoreList, 3)
            beam:Destroy()
        end)

        spawn(function()
            game:GetService("RunService").Heartbeat:Connect(function()
                beam.Size = Vector3.new(beam.Size.X - 0.01, beam.Size.Y - 0.01, beam.Size.Z)
                beam.Transparency = beam.Transparency + 0.05
            end)
        end)

        print(part)

        if part then print'oof'
            local humanoid = part.Parent:FindFirstChild("Humanoid")

            if not humanoid then
                humanoid = part.Parent.Parent:FindFirstChild("Humanoid")
            end

            if humanoid then
                mouse.Icon = "rbxassetid://253263084"
                delay(0.2, function()
                    mouse.Icon = "rbxassetid://251138645"
                end)
                remotes['Damage']:FireServer(humanoid)
                script.Hit:Play()
            end
        end
    end)
end)