DataStore. Join and quick leave server wipes out data

[777PerfectPlayer777 (NightPlayer)]

Hello. I have big problem with my savedata. I wiped out my saves in studio while i started and stopped game quick. Then some error like “Player didnt loaded because left server bla bla”
And then I started again i realized my savedata was at state like at first join.

local DataStoreService=game:GetService("DataStoreService")
local datasave = DataStoreService:GetDataStore("data")

Players.PlayerAdded:Connect(function(player)	
    local data = require(pathtomodule)
    local playerdata = nil

	local success, playerdata = pcall(function()

		return datasave:GetAsync(player.UserId) 

	end)
	
	if not playerdata then
		
		playerdata = {		
		stuff = 0,		
		}
		local success, errmsg = pcall(function()

			datasave:SetAsync(player.UserId, playerdata) 

		end)		
	end
        data.stuff=playerdata.stuff  --first i copy playerdata to module in serverscript

end)
Players.PlayerRemoving:Connect(PlayerLeaving)(

local data = require(pathtomodule)
				
	local playerdata = {
		
		stuff=data.stuff
	
	}			
	local sucess , errormsg = pcall(function()
		
		datasave:SetAsync(player.UserId, playerdata)
		
	end)
end)

[a19_9 (Nol)]

you should only save data after you validate its already been loaded, you can use attribute on a player to easily do this

local DataStoreService=game:GetService("DataStoreService")
local datasave = DataStoreService:GetDataStore("data")

Players.PlayerAdded:Connect(function(player)	
   local data = require(pathtomodule)
   local playerdata = nil

   local success, playerdata = pcall(function()

   	return datasave:GetAsync(player.UserId) 

   end)

   if not playerdata then

   	playerdata = {		
   		stuff = 0,		
   	}
   	local success, errmsg = pcall(function()

   		datasave:SetAsync(player.UserId, playerdata) 

   	end)		
   end
   data.stuff=playerdata.stuff  --first i copy playerdata to module in serverscript
   player:SetAttribute('DataLoaded', true)

end)
Players.PlayerRemoving:Connect(PlayerLeaving)(

if PlayerLeaving:GetAttribute('DataLoaded') then
   local data = require(pathtomodule)

   local playerdata = {

   	stuff=data.stuff

   }			
   local sucess , errormsg = pcall(function()

   	datasave:SetAsync(player.UserId, playerdata)

   end)
end	

end)

[777PerfectPlayer777 (NightPlayer)]

I hope that works. Thanks for help.