Does filtering effect what properties you can get in Workspace?

I have a script here:

music = game.Workspace.Music:GetChildren()

for i, tune in pairs(music) do
	tune:Play()
	wait(tune.TimeLength)
end

It's pretty simple and works fine when filtering is not on. My music will be played through one at a time, and the appropriate amount of time will pass until the next track plays. However, when I turn on filtering, it doesn't seem to work properly. All of the music will play at the same time. I have a feeling that it has to do with the fact that I'm trying to get the TimeLength property from a Workspace object. Can someone explain to me where I am going wrong?