Moving platform gets stuck in place?

heres the code

local y = script.Parent.CFrame.Y
local part = script.Parent
local button = workspace.Button2.button2.scriptpart2
local e = 1
button.Touched:Connect(function(hit)
	if hit.Parent:FindFirstChild('Humanoid') then
		repeat wait() until button.Touched 
			while true do
				
				part.CFrame	= CFrame.new(36, y + 0.05 * e, -36)
			wait(0.05)
			print("height is" and y)
			print(script.Parent.CFrame.Y)
			if y > 20 or y < 3 then 
				print('We have triggered')
					e = e * -1
					wait(3)
			  	end
			   
			end
		end
	end
)