I recently got in developing a plugin to speed up my game development for a project I am working on, and I found the UI Text Size on the Plugin isn’t the same for all UI Text Boxes.
Here is an example:

The UI Text Button Code:
local testButton = Instance.new("TextButton")
testButton.BorderSizePixel = 0
testButton.TextSize = 20
testButton.TextColor3 = Color3.new(1,0.2,0.4)
testButton.AnchorPoint = Vector2.new(0.5,0)
testButton.Size = UDim2.new(1,0,0.5,0)
testButton.Position = UDim2.new(0.5,0,0,0)
testButton.SizeConstraint = Enum.SizeConstraint.RelativeXY
testButton.Text = "Button1"
testButton.Parent = WindowWidget
local testButton2 = Instance.new("TextButton")
testButton2.BorderSizePixel = 0
testButton2TextSize = 20
testButton2.TextColor3 = Color3.new(1,0.2,0.4)
testButton2.AnchorPoint = Vector2.new(0.5,0.5)
testButton2.Size = UDim2.new(1,0,0.5,0)
testButton2.Position = UDim2.new(0.5,0,0.75,0)
testButton2.SizeConstraint = Enum.SizeConstraint.RelativeXY
testButton2.Text = "Button2"
testButton2.Parent = WindowWidget
I am unsure if I missed something, or if this is a bug, help will be very appreciated.

No worries.