Why does my mobs get glitched when a target [Player] leaves the game?

So in this script, i made it so when a player is in range of the mob, it will try and hunt down the player. But when a player leaves they get glitched and will stay still. They still do damage though

local pathfind = game:GetService("PathfindingService")
local statsfolder = script.Parent:WaitForChild("STATSFOLDER")
local humanoid = script.Parent:WaitForChild("Humanoid")
local mindamage = statsfolder:WaitForChild("MinDamage")
local maxdamage = statsfolder:WaitForChild("MaxDamage")
local visiondistance = statsfolder:WaitForChild("VisionStud")
local targetvalue = statsfolder:WaitForChild("Target")
local position = statsfolder:WaitForChild("Position")
local torso = script.Parent:WaitForChild("Torso")
local enabled = false
math.randomseed(tick()-wait(1))

--Damaging Player

torso.Touched:connect(function(part)
    if part.Parent:FindFirstChild("Humanoid") and part.Parent.Name ~= "NPC" and enabled == false then
        enabled = true
        local humanoid = part.Parent:WaitForChild("Humanoid")
        humanoid:TakeDamage(math.random(mindamage.Value, maxdamage.Value))
        wait(2)
        enabled = false
    else
        enabled = true
        humanoid.Jump = true
        wait(1.5)
        enabled = false
    end
end)

function FindHumanoid()
    local allplayers = game.Players:GetPlayers()
    for i, v in pairs(allplayers) do
        if v.Character and v.Character:FindFirstChild("Humanoid").Health > 0 then

            local targettorso = v.Character:FindFirstChild("Torso")
            local location = (torso.Position - targettorso.Position).magnitude
            if location < visiondistance.Value then
                targetvalue.Value = v.Character
            else            
            end
        end
    end
end

--If player health is higher then 0 then they follow the player

while humanoid.Health > 0 do
    FindHumanoid()
    if targetvalue.Value then
        local rtorso = targetvalue.Value:FindFirstChild("Torso")
        if rtorso then
            local path = pathfind:ComputeSmoothPathAsync(torso.Position, rtorso.Position, 200)
            local check = path:GetPointCoordinates()
            for i = 1, #check do
                local singularpoints = check[i]
                humanoid:MoveTo(singularpoints)
            end
        else        
        end
    else

    end
    wait(0.5)
end