I have a custom rig animation that uses basically the same code as the ROBLOX wiki for animations. It is in a place with Filtering Enabled on, and the script is a LocalScript. The animations work when I am in a studio play, but doesn't when I am on a server test. The animation will work on server side, but won't work on client side. I did however, manage to fix this by taking the model in the studio explorer (while playing the game) and moving it into my Player's PlayerGui, then into the Player's Camera, and for some reason it played. Why is this, and is there any easier way to make it play on client side?
local animation = Instance.new("Animation")
animation.AnimationId = "http://www.roblox.com/Asset?ID=548213534"
local animTrack = nil
local canPlay = true
function playAnim(Source)
if canPlay then
local player = script.Parent
canPlay = false
animTrack = player.Humanoid:LoadAnimation(animation)
canPlay = true
animTrack:Play()
end
end
playAnim(script.Parent)

2 comments
For some strange reason looped animations do no replicate to new players once they are played, you can quickly test this by adding a wait in before you play it. But this will not resolve the problem.
In 2014 this error was valid as well, but it was patched after it was brought up on the dev forum. Recently, I suppose the error has resurfaced. https://devforum.roblox.com/t/animations-do-not-replicate-with-filtering-enabled-cropped-up-again/9412