Animation is glitching and bugging out in play mode

[justin2710 (Him)]

1. What do you want to achieve? Keep it simple and clear!

I recently learned how to make cutscenes, in studio the animation is fine but when I playtest it, my joints go haywire.

2. What is the issue? Include screenshots / videos if possible!

External Media

THIS video shows you what the animation looks like in studio, and what it looks like after.

3. What solutions have you tried so far? Did you look for solutions on the Developer Hub?

Yep.

local debounce = false
function activate()
	print("Flag 1")
	local character : Model = script.Parent.Parent
	local humanoid = character:FindFirstChildWhichIsA("Humanoid")
	local torso : BasePart = character.Torso
	local sound = game.ServerStorage.Sounds.Rengoku:Clone()
	sound.Parent = character.HumanoidRootPart
	customFuncs.setWalkSpeed(humanoid,0)
	-- add parts
	local vfxRengoku = serverStorage.Cutscene["VFX(RENGOKU)"]:Clone()
	vfxRengoku.Parent = character
	local camera = serverStorage.Cutscene.CameraModel:Clone()
	camera.Parent = character
	print("Flag 2")
	for i, v in pairs(vfxRengoku:GetChildren()) do
		if v:IsA("Script") then continue end
		
		if v.Name ~= "katana" then
			v.Motor6D.Part0 = torso;
		else
			v.Motor6D.Part0 = character["Right Arm"];
		end
		
	end
	camera.Camera.Motor6D.Part0 = torso
	print("Flag 3")
	repeat wait() until character:FindFirstChild("CameraModel")
	-- tweek camera
	--game.ReplicatedStorage.Remotes.Camera:FireClient(game.Players:GetPlayerFromCharacter(character),true,character.CameraModel.Camera);
	-- animation
	local track = character:FindFirstChildWhichIsA("Humanoid"):LoadAnimation(script.Animation)
	sound:Play()
	track:Play()
	track.Ended:Wait()
	--game.ReplicatedStorage.Remotes.Camera:FireClient(game.Players:GetPlayerFromCharacter(character),true,character.CameraModel.Camera);
	customFuncs.setWalkSpeed(humanoid,50)
	-- post animation (dragon)
	vfxRengoku.DragonHead.DragonHeadInner.Transparency = 0;
	vfxRengoku.DragonHead.DragonHeadOuter.Transparency = 0.4;
	print("Flag 4")
	
	-- reset player
	sound.Ended:Wait()
	humanoid:TakeDamage(99999)
	print("Flag 5")
end

script.Parent.Activated:Connect(function()
	if debounce then return end
	debounce = true;
	activate()
end)

[justin2710 (Him)]

I FIXED IT!!! Turns out, the interpolation modes were bugging out the animation. I changed all the keyframes to linear and it worked!