Text button not fading out? Uses threading/spawn()

I've recently been experiment with spawn(), which allows you to run two while loops simultaneously, due to the spawn() event creating a thread for each function called inside the parentheses of spawn(). However, I'm not sure why my textbutton is not fading out. By creating a function that counts for when the button's BackgroundTransparency is less than or equal to x, I'm still stumped.

Here's the current code:

function campaign_FadeOut()
	while campaign.BackgroundTransparency <= 0.8 do
		campaign.BackgroundTransparency = campaign.BackgroundTransparency + .01
		wait()
	end
end

-- hierarchy is fine; I've put it through multiple tests, and they all work
if script.Parent.MainMenu.Menu.Start.LocalScript.Disabled == true then
	UserInputService.InputBegan:connect(function(key) -- I still don't understand the bool inside the function, so I left it out; going to be reading up on that soon.
		if key.UserInputType == Enum.UserInputType.Keyboard then
			if key.KeyCode == Enum.KeyCode.Down then
				if campaign.BackgroundTransparency <= 0.5 then
					print("Woo, worked!")
					spawn(multiplayer_FadeIn) -- the fadeIn function works fine
					spawn(campaign_FadeOut) -- this function screws up
				end
			end
		end
	end)
end

Thoughts and suggestions are appreciated. Thanks!