Tween doesn't play properly the first time

[delicate anvil]

local function barrage(player)
    local barrageTween = tweenService:Create(player.Character.Weld,TweenInfo.new(0.1, Enum.EasingStyle.Linear, Enum.EasingDirection.In),{C1 = CFrame.new(0,0,2)})
    barrageTween:Play()
end

Tween function ^

elseif key == "R" then
        if standStage == false then
            for i,v in pairs(stand:GetChildren()) do
                if v:IsA("BasePart") and v.Name ~= "HumanoidRootPart" then
                    local tween = tweenService:Create(v,TweenInfo.new(0.1, Enum.EasingStyle.Linear, Enum.EasingDirection.In),{Transparency = 0})
                    tween:Play()
                end
                standStage = true
            end    
        end
        barrage(player)
        heavyanim:Play()
        task.wait(heavyanim.Length)
        barrageEnd(player)
    end

[terse ether]

Maybe it isn't loaded in correctly first time