Some players don't spawn on the Checkpoint they are on?

Hi I am Rob and I have been using Roblox Studio for a week.

So basically I have been trying to create a checkpoint system using a StartSpawn and a few Checkpoint blocks. It worked perfectly for all the users who played but one of my friend says that even if touched his current checkpoint, he would still respawn back to the StartSpawn If there is a better way of doing this or some improvements on my script please leave an answer!

My script :

local spawn = script.Parent
spawn.Touched:connect(function(hit)
if hit and hit.Parent and hit.Parent:FindFirstChild("Humanoid") then
local player = game.Players:GetPlayerFromCharacter(hit.Parent)
local checkpointData = game.ServerStorage:FindFirstChild("CheckpointData")
if not checkpointData then
checkpointData = Instance.new("Model", game.ServerStorage)
checkpointData.Name = "CheckpointData"
end
local checkpoint = checkpointData:FindFirstChild(tostring(player.userId))
if not checkpoint then
checkpoint = Instance.new("ObjectValue", checkpointData)
checkpoint.Name = tostring(player.userId)
player.CharacterAdded:connect(function(character)
wait()
character:WaitForChild("HumanoidRootPart").CFrame = game.ServerStorage.CheckpointData[tostring(player.userId)].Value.CFrame + Vector3.new(0, 4, 0)
end)
end
checkpoint.Value = spawn
end
end)