Something weird is happening to my text?

I am making a game where server scripts send text messages to client through a GUI, but this is the result:

Image

This is the function that handles text:

function SendLine(Text, _Color, NoTime)
    print(Text)
    if LocalPlayer:FindFirstChild("PlayerGui") and LocalPlayer:FindFirstChild("PlayerGui").ClassName == "PlayerGui" then
        NoTime = NoTime or false
        local NewText = (" %s - %s"):format(tostring(TimeStamp()), Text:gsub("\0", "\5"))
        if NoTime == true then
            NewText = (" > %s"):format(Text:gsub("\0", "\5"))
        end
        local Label = Instance.new("TextLabel", Content)
        Label.Name = "Line"
        Label.ZIndex = 2
        Label.BackgroundTransparency = 1
        Label.BorderSizePixel = 0
        Label.Text = tostring(NewText)
        if type(_Color) == "string" then
            Label.TextColor3 = BrickColor.new(_Color).Color
        else
            Label.TextColor3 = _Color
        end
        Label.TextStrokeTransparency = 0.99
        Label.Font = "SourceSansBold"
        Label.FontSize = "Size14"
        Label.TextWrapped = false
        Label.Size = UDim2.new(1, 0, 0, 15)
        Label.Position = UDim2.new(0, 0, 0, CalculatePosition(Content))
        Label.TextXAlignment = "Left"
        Label.TextYAlignment = "Top"
        if #Content:GetChildren() > 14 then
            Content.CanvasSize = UDim2.new(5, 0, 0, CalculateCanvasSize(Content))
            Content.CanvasPosition = Vector2.new(0, (Content.CanvasSize.Y.Offset - Content.AbsoluteSize.Y) + 5)
        end
    end
end

Is this a known issue or is it my fault?