Data is not a valid member of player?

Everytime I add a new pet into my game, i get the error "Data is not a valid member of player, it randomly goes away usually but its annoying how do i fix that?

script:

local Players = game:GetService("Players")
local Datastore = game:GetService("DataStoreService"):GetDataStore("PlayerData")
local RS = game:GetService("ReplicatedStorage")

function getLevel(totalXP)
    local Increment = 0
    local RequiredXP = 100
    for i = 0, RS.Pets.Settings.MaxPetLevel.Value do
        RequiredXP = 100 + (25*i)
        if totalXP >= (100*i) + Increment then
            if i ~= RS.Pets.Settings.MaxPetLevel.Value then
                if totalXP < ((100*i) + Increment) + RequiredXP then
                    return i
                end
            else
                return i
            end
        end
        Increment = Increment+(i*25)
    end
end

Players.PlayerRemoving:Connect(function(plr)
    local Pets = plr.Pets
    local Data = plr.Data

    local PetData = {}
    local PlayerData = {}

    for _,PetObject in pairs(Pets:GetChildren()) do
        PetData[#PetData + 1] = {
            Name = PetObject.Name,
            TotalXP = PetObject.TotalXP.Value,
            Equipped = PetObject.Equipped.Value,
            PetID = PetObject.PetID.Value,
            Multiplier1 = PetObject.Multiplier1.Value,
            Multiplier2 = PetObject.Multiplier2.Value,
            Type = PetObject.Type.Value
        }
    end
    for _,DataValue in pairs(Data:GetChildren()) do
        PlayerData[#PlayerData + 1] = {
            Name = DataValue.Name,
            ClassName = DataValue.ClassName,
            Value = DataValue.Value
        }
    end

    Datastore:SetAsync(plr.UserId, {["PetData"] = PetData, ["PlayerData"] = PlayerData})
end)

Players.PlayerAdded:Connect(function(plr)
    local Pets = Instance.new("Folder")
    local Data = Instance.new("Folder")

    local SavedData = Datastore:GetAsync(plr.UserId)

    Pets.Name = "Pets"
    Data.Name = "Data"

    if SavedData ~= nil then
        local PetData = SavedData.PetData
        local PlayerData = SavedData.PlayerData
        for i,v in pairs(PetData) do
            local PetObject = RS.Pets.PetFolderTemplate:Clone()
            local Settings = RS.Pets.Models:FindFirstChild(v.Name).Settings
            local TypeNumber = RS.Pets.CraftingTiers:FindFirstChild(v.Type).Value
            local Level = getLevel(v.TotalXP)
            PetObject.Name = v.Name
            PetObject.Equipped.Value = v.Equipped
            PetObject.TotalXP.Value = v.TotalXP
            PetObject.Multiplier1.Value = Settings.Multiplier1.Value * (RS.Pets.Settings.CraftMultiplier.Value ^ TypeNumber) + (Settings.LevelIncrement.Value * Level)
            PetObject.Multiplier2.Value = Settings.Multiplier2.Value * (RS.Pets.Settings.CraftMultiplier.Value ^ TypeNumber) + (Settings.LevelIncrement.Value * Level)
            PetObject.PetID.Value = v.PetID
            PetObject.Type.Value = v.Type
            PetObject.Parent = Pets
        end
        for i,v in pairs(script.Data:GetChildren()) do
            local DataValue = v:Clone()
            local DataTable = nil
            DataValue.Parent = Data
            for i,v in pairs(PlayerData) do
                if v.Name == DataValue.Name then
                    DataTable = v
                end
            end
            if DataTable ~= nil then
                if DataValue.Name == "MaxStorage" or v.Name == "MaxEquipped" then
                    DataValue.Value = RS.Pets.Settings:FindFirstChild("Default".. DataValue.Name).Value
                else
                    DataValue.Value = DataTable.Value
                end
            else
                if DataValue.Name == "MaxStorage" or v.Name == "MaxEquipped" then
                    DataValue.Value = RS.Pets.Settings:FindFirstChild("Default".. DataValue.Name).Value
                end
            end
        end
    else
        for i,v in pairs(script.Data:GetChildren()) do
            local DataValue = v:Clone()
            DataValue.Parent = Data
            if DataValue.Name == "MaxStorage" or v.Name == "MaxEquipped" then
                DataValue.Value = RS.Pets.Settings:FindFirstChild("Default".. DataValue.Name).Value
            end
        end
    end

    game.Players.PlayerRemoving:Connect(function(player)
        Datastore:SetAsync(player.UserId, player:FindFirstChild("Value").Value)
    end)

    Pets.Parent = plr
    Data.Parent = plr
end)