AnimationTrack:AdjustSpeed(0) is not working at "all"?

The meaning of the title, means my code only worked at "half".

Let me post my code first.

local Poisonous = workspace:WaitForChild("Intermission").Poisonous --boolValue
local Anim = Instance.new("Animation")
Anim.AnimationId = "rbxassetid://3616641128"

function freezeAnimationAtTime(animationTrack, timePosition) 
	wait(timePosition)
	animationTrack.TimePosition = timePosition
	animationTrack:AdjustSpeed(0)
end

Poisonous.Changed:Connect(function(Value)
	if Poisonous.Value == true then
		CurrentCamera.CameraSubject = character.Head
		freezeAnimationAtTime(humanoid:LoadAnimation(Anim),4.5)
		humanoid:LoadAnimation(Anim):Play()
	end
end)

These code works perfectly, but there's something happened.

in the single player test, when the animation played, it still not pause at 4.5 second.

in the two player test, when the animation played, it still not pause at 4.5 second. BUT

when they watch other side, they DO paused!

is there any problem in my code? how to fix it or it just glitched?

By the way, there's not all my codes. If you request more information i'll update them.

cheers.