Its not an error, its a warning, i dont think its important, unless you spam save, it just means: “hey im gonna save this but if my queue fills im not be able to save new requests so be slower”
if game:GetService("RunService"):IsStudio() then return end
What happens here is when u stop the server, the player leaves which will save their data and the data will save a second time since you hooked the function to game:BindToClose