My game is filtering enabled and I don't clone the GUI with a local script, I use a normal one. The GUI is for a role-play name that is above the player's head. The GUI only shows for the player that it is on top of and not for anyone else. I don't know if this has to do with filtering enabled and I don't think the code has to do with this but just in case it does, here it is.
players = game:GetService("Players")
rf = game:GetService("ReplicatedFirst")
players.PlayerAdded:connect(function(plr)
plr.CharacterAdded:connect(function(char)
local gui = script.NameGUI:Clone()
gui.Adornee = char:WaitForChild("Head")
gui.Parent = gui.Adornee
gui:WaitForChild("PlrName").Text = rf.BFs.GetValue:Invoke("PlrName",true)
gui.PlrName.TextColor3 = rf.BFs.GetValue:Invoke("PlrNameColor")
end) end)

2 comments
Not enough explanation...
Basically, the Billboard GUI doesn't show for any other player. It only shows for the local player.