when the npc attacks it slows down but never speeds up again, any clue why?

there are no error code, it just doesn't seem to work

local attackCooldown = 1 
local attackWindup = 0.5
local attackRange = 3
local attackDamage = 20

local char = script.Parent.Parent
local hum = char:WaitForChild("Humanoid")
local originalWalkSpeed = hum.WalkSpeed

local canAttack = true

script.Parent.AttackRemote.Event:Connect(function(plrRoot)

	if not canAttack then return end
	canAttack = false
	
	hum.WalkSpeed = 0.1

	local anim = Instance.new("Animation")
	anim.AnimationId = "rbxassetid://7215836748"
	local playAnim = hum:LoadAnimation(anim)
	playAnim:Play()

	wait(attackWindup)
	local newDistance = (char.HumanoidRootPart.Position - -plrRoot.Position).magnitude
	if newDistance <= attackRange + 5 then 
		
	if plrRoot.parent.Player.isBlocking.Value == true then
		attackDamage *= 0.5
	end
	plrRoot.Parent.Humanoid:takeDamage(attackDamage)

	wait(attackCooldown)
	hum.WalkSpeed = originalWalkSpeed
	canAttack = true
	
	end
	end)

I think the NCP might be breaking because you defined origin walkspeed as the humanoid's walkspeed. This means when you use originalWalkSpeed, it gets the humanoid's current walkspeed. You're basically telling the script to set the humanoid's walkspeed to itself. You can fix this by writing something similar to this:

local OriginWalk = instance.new("NumberValue", char)
OriginWalk.Value = hum.Walkspeed

You can then use this value later in the script, rather than originalWalkSpeed.