Player location not always saving?

I'm very new to datastores and I just created a script that saves the player's location. The script works, but sometimes it goes back to where they were a few seconds ago. Im getting an error in the output which I think may be the cause. The error says:

"DataStore request was added to queue. If request queue fills, further requests will be dropped. Try sending fewer requests.Key = 137521187"

Here is my code:

local dss = game:GetService("DataStoreService")
local ds = dss:GetDataStore("LocationData")

local sessionData = {}

local function addPlayer(player)
    local data = ds:GetAsync(player.UserId)
    local char = player.Character or player.CharacterAdded:Wait()
    local hrp = char:WaitForChild("HumanoidRootPart")
    if not data then
        sessionData[player] = { loc = { hrp.CFrame:GetComponents() } }
    else
        sessionData[player] = data
        local cf = CFrame.new(table.unpack(sessionData[player].loc))
        wait()
        hrp.CFrame = cf
    end
end

local function saveLocation(player)
    local char = player.Character or player.CharacterAdded:Wait()
    local hrp = char:WaitForChild("HumanoidRootPart")
    sessionData[player].loc = { hrp.CFrame:GetComponents() }
    ds:SetAsync(player.UserId, sessionData[player])
end

local function saveLoop()
    while true do
        wait(3)
        for ply, v in pairs(sessionData) do
            saveLocation(ply)
        end
    end
end

local function removePlayer(player)
    saveLocation(player)
    sessionData[player] = nil
end

game.Players.PlayerAdded:Connect(addPlayer)
game.Players.PlayerRemoving:Connect(removePlayer)

spawn(saveLoop)