My zombie jerks back while walking towards the player but walks fine while roaming randomly?

i'm having a problem with my zombie. i haven't really ever successfully made a zombie before, this is my first time. pretty much what this zombie does is it walks around its spawn point, and when it roams too far away, it walks back to its spawn point. when a player comes near it, it follows the player. the problem im having is that the zombie makes a jerking, or twitching motion which is not in it's animation while walking towards the player. example

script inside of the zombie:

local zombie = script.Parent.Parent
local anim = zombie.Animation
local hum = zombie.Humanoid
local animtrack = hum:LoadAnimation(anim)
local Distance = 30
local target = nil
local anim_Playing = false
wait(3)

function Roam()
	animtrack:Play()
	hum:MoveTo(zombie.UpperTorso.Position + Vector3.new(math.random(-5,5),0,math.random(-5,5)))
	hum.MoveToFinished:Wait(2)
	if (zombie.UpperTorso.Position - game.Workspace.Spawn.Position).magnitude > 30 then
		local path = game:GetService("PathfindingService"):ComputeRawPathAsync(zombie.UpperTorso.Position, game.Workspace.Spawn.Position + Vector3.new(math.random(-2,2),0,math.random(-2,2)), 200)
		local points = path:GetPointCoordinates()
		if anim_Playing == false then
		animtrack:Play()
		anim_Playing = true
		end
		for p = 1, #points do
			hum:MoveTo(points[p])
			hum.MoveToFinished:Wait()
		end
	end
end


while wait() do
	for i,v in pairs (game.Players:GetChildren()) do
		local plr_Distance = (v.Character.UpperTorso.Position - zombie.UpperTorso.Position).magnitude
		if plr_Distance <= Distance then
			local plrpath = game:GetService("PathfindingService"):ComputeRawPathAsync(zombie.UpperTorso.Position, v.Character.UpperTorso.Position, Distance)
			local plrpoints = plrpath:GetPointCoordinates()
			for p = 1, #plrpoints do
				wait(.1)
				hum:MoveTo(plrpoints[p])
			end
			if plr_Distance <= 3 then
				wait(1)
				if plr_Distance <=3 then
					v.Character.Humanoid.Health = v.Character.Humanoid.Health - 20
				end
			end
		else
			Roam()
		end
	end
end