GUI/Text button goes invisible when called to move?

https://gyazo.com/d6bdef1d733c42889c8100f99d2552ec

but=script.Parent
pos=UDim2.new(0.006, 0, 0.917, 0)
but.MouseEnter:Connect(function()
    local db=false

    if not db then
        db=true
        but.Position=pos
        but.ImageColor3=Color3.new(170, 120, 200)
        print(but.Position)
        wait(2)
        db=false

    end
end)

All this script does is move the 'shop' button down only slightly, however when called it goes invisible (but still selectable)? Any idea how I can fix this? p.s the button is made with the roundifier plugin, giving the textbutton an image