Viewport avatars glitching

Hi!
The title is all that’s needed, the avatars in my viewports are randomly glitching.

What is wrong?
Thanks!

local Humanoid = script.Parent
local humanoidDescription = game.Players:GetHumanoidDescriptionFromUserId(1649205360)
Humanoid:ApplyDescription(humanoidDescription)
local back = Humanoid.Parent.Parent
Humanoid.Parent.Parent = game.Workspace
task.wait() --This waits for Roblox welds to load
Humanoid.Parent.Parent = back

while task.wait(10) do
	humanoidDescription = game.Players:GetHumanoidDescriptionFromUserId(1649205360)
	Humanoid:ApplyDescription(humanoidDescription)
end
local cam = Instance.new('Camera')
cam.Parent = script
script.Parent.CurrentCamera = cam
local CamPart = script.Parent.Dummy.cam--Path To Dummy's 'Cam' part
	cam.CFrame = CamPart.CFrame

Just curious, what’s the reason for using ViewportModels here over using an ImageLabel?
https://developer.roblox.com/en-us/articles/Content#rbxthumb

Better way for live updating avatar? - Help and Feedback / Scripting Support - DevForum | Roblox

Does anybody have an answer?

So what’s glitching in there, it just doesn’t show the character model sometimes?

It does not load stuff 1/2 of the time.