How to stop Tween Service from changing orientation?

I have this code I found on the DevForms, however when I execute the code the model goes into a random orientation rather than a straight tween.

local function tweenModel(model, CF)
    local CFrameValue = Instance.new("CFrameValue")
script.Parent.Cash.PrimaryPart = MainPart
    CFrameValue.Value = model:GetPrimaryPartCFrame()

    CFrameValue:GetPropertyChangedSignal("Value"):Connect(function()
        model:SetPrimaryPartCFrame(CFrameValue.Value)
    end)

    local tween = tweenService:Create(CFrameValue, info, {Value = CF})
    tween:Play()

    tween.Completed:Connect(function()
        CFrameValue:Destroy()
    end)
end

I execute the function with this:

        tweenModel(MainPart.Parent, CFrame.new(script.Parent.Main_.Position))

This is what happens

How can I fix the problem so it evenly tweens out properly?