I made a pretty basic script to test this out.
-- Parent is TextButton, Parent.Parent is BillBoard gui.
script.Parent.MouseButton1Up:Connect(function()
script.Parent.Text = "NO U"
wait(3)
script.Parent.Text = "Click me (test)"
end)
Nothing happens, no errors, NOTHING! I also tried it with a normal non-local script just in case it doesn't work because it's a non-local instance, that didn't help. This works on a SurfaceGui though.
Help is appreciated, thanks!

4 comments
Is it a localScript, and is FE on?
Yes, both local script and FE. I have also tried it with normal script, but I'm mainly using local script
Then, if FE is on, it has to be FE compatible.
it just changes the text, it should work regardless of FE on a local script, but it doesn't work