SetPrimaryPartCFrame condenses my model into one position! Help?

local PlacementItem = nil
local PreviousItem = nil
local HoldingR = false

spawn(function()
    while true do
        game:GetService('RunService').RenderStepped:wait()
        local Mouse = Player:GetMouse()
        if PlacementItem ~= nil and PreviousItem == PlacementItem then -- Same item
            local PlaceItem = Player.Character:FindFirstChild("Item") or PlacementItem:Clone()
            Mouse.TargetFilter = PlaceItem
            PlaceItem.Parent = Player.Character
            local PIC = PlaceItem:GetChildren()
            for i = 1,#PIC do
                if PIC[i].Transparency ~= 1 then
                    PIC[i].Transparency = 0.5
                    PIC[i].CanCollide = false
                end
            end
            if HoldingR == false then
                PlaceItem:MoveTo(Mouse.Hit.Position)
            elseif HoldingR == true then
                PlaceItem:SetPrimaryPartCFrame(CFrame.new(PlaceItem.PrimaryPart.Position,Vector3.new(Mouse.Hit.Position.X,PlaceItem.PrimaryPart.Position.Y,Mouse.Hit.Position.Z)))
            end
        elseif PlacementItem ~= nil and PreviousItem ~= PlacementItem then -- Different Items
            PreviousItem = PlacementItem
        elseif PlacementItem == nil then
            if Player.Character:FindFirstChild("Item") then
                Player.Character:FindFirstChild("Item"):Destroy()
            end
        end
    end
end)

Aight so I see nothing wrong with this code; however, sometimes my model collapses into one.

https://gyazo.com/188c817a4c99a8561f83c1d5936a960e.png Before spamming R

https://gyazo.com/bbbb25233286c23a24ce6c1858a2851a.png After spamming R

https://gyazo.com/cd9fb3f2653ad7450d92d7062cf056fa.gif Me spamming R in a GIF