Sprites are moving when they shouldn't?

(Yes, I'm making a sprite-based game. Don't ask why.)

local label = script.Parent
local RunService = game:GetService("RunService")
local Debris = game:GetService("Debris")
local length = label:WaitForChild("Length")
local width = label:WaitForChild("Width")
local angle = label:WaitForChild("Angle")
local delaytime = label:WaitForChild("Delay")
local life = label:WaitForChild("Lifetime")
local t = label:WaitForChild("Transparency")

local delayLine = Instance.new("Frame")
delayLine.Parent = label
delayLine.Name = "DelayLine"
delayLine.Size = UDim2.new(0, 1, length.Value, 0)
delayLine.AnchorPoint = Vector2.new(0, 0)
delayLine.BorderSizePixel = 0
delayLine.BackgroundColor3 = Color3.fromRGB(255, 255, 255)
delayLine.BackgroundTransparency = 0.5
delayLine.Position = UDim2.new(0, 0, 0, 0)

local hitbox = Instance.new("Frame")
hitbox.Parent = label
hitbox.AnchorPoint = Vector2.new(0.5, 0.5)
hitbox.Size = UDim2.new(0.33, 0, 1, 0)
hitbox.Position = UDim2.new(0.5, 0, 0.5, 0)
hitbox.BackgroundTransparency = 1

local hitboxScript = game.ReplicatedStorage.BulletScripts:WaitForChild("LinearHitboxScript"):Clone()
hitboxScript.Parent = hitbox
hitboxScript.Disabled = true

delay(delaytime.Value, function()
	label:TweenSize(UDim2.new(0, width.Value, 0, length.Value), "Out", "Quad", 0.25, false, function()
		Debris:AddItem(label, life.Value)
	end)
end)

function getRealAngle(a)
	local val = math.abs(a - 180)
	
	if a > 180 then
		val = val * -1
	end
	
	return val
end

label:GetPropertyChangedSignal("Size"):Connect(function()
	if label.Size == UDim2.new(0, 1, 0, 1) then
		delayLine.Visible = true
		label.ImageTransparency = 1
		hitboxScript.Disabled = true
	else
		delayLine.Visible = false
		label.ImageTransparency = t.Value
		hitboxScript.Disabled = false
	end
end)

RunService.RenderStepped:Connect(function()
	label.Rotation = getRealAngle(angle.Value)
end)

When the sprite is created, its size is set to UDim2.new(0, 1, 0, 1). After a certain amount of time passes, the sprite expands to its true size, determined by the values of Length and Width.

However, when the sprite's size changes, it moves towards the bottom of the screen, even though I don't have anything that changes the position in the script. Is there a way to fix it?

Here's the function that creates these sprites, in case it helps with figuring out the problem:

function lib:CreateStraightLaser(x, y, angle, length, width, delaytime, graphic, timer)
	local RealLaser = getShotData(graphic)
	local BoundBox = RealLaser.Bound
	local sLaserScript = ExtraScriptsDirectory:WaitForChild("StraightLaserScript")
	
	local sLaser = Instance.new("ImageLabel")
	sLaser.Name = RealLaser.Name
	sLaser.Position = UDim2.new(0, x, 0, y)
	sLaser.Size = UDim2.new(0, 1, 0, 1)
	sLaser.AnchorPoint = Vector2.new(0.5, 0)
	sLaser.BackgroundTransparency = 1
	sLaser.Image = ShotSheetImage
	sLaser.ImageRectOffset = BoundBox.Min
	sLaser.ImageRectSize = Vector2.new(BoundBox.Width, BoundBox.Height)
	sLaser.ImageTransparency = 1
	
	local l = Instance.new("NumberValue")
	l.Parent = sLaser
	l.Name = "Length"
	l.Value = length
	
	local a = Instance.new("NumberValue")
	a.Parent = sLaser
	a.Name = "Angle"
	a.Value = angle
	
	local w = Instance.new("NumberValue")
	w.Parent = sLaser
	w.Name = "Width"
	w.Value = width
	
	local d = Instance.new("NumberValue")
	d.Parent = sLaser
	d.Name = "Delay"
	d.Value = delaytime
	
	local life = Instance.new("NumberValue")
	life.Parent = sLaser
	life.Name = "Lifetime"
	life.Value = timer
	
	local t = Instance.new("NumberValue")
	t.Parent = sLaser
	t.Name = "Transparency"
	t.Value = RealLaser.Transparency
	
	local newLaserScript = sLaserScript:Clone()
	newLaserScript.Parent = sLaser
	newLaserScript.Disabled = false
	
	sLaser.Parent = getLocalPlayerGui()
	
	return sLaser
end