Why is my placement system acting weird?

So im making a placement system right now and something weird is happening the code and a short vid are below

wait()
local plan = game.ReplicatedStorage.Floor.Selection
local build = game.ReplicatedStorage.Floor.floor
local pos = Vector3.new(0,0,0)
script.Parent.Equipped:Connect(function(mouse)
    local plan1 = plan:Clone()
    plan1.Parent = game.Workspace
    mouse.Button1Down:connect(function()
        print("ok")
        local build1 = build:Clone()
        build1.Parent = game.Workspace
        build1.Position = plan1.Position
    end)
    while wait() do
        pos = Vector3.new(math.floor(mouse.Hit.p.X),math.floor(mouse.Hit.p.Y),math.floor(mouse.Hit.p.Z))
        plan1.Position = pos+Vector3.new(0,0,0)
    end
end)

https://medal.tv/clips/33015914/d13373Haqm99 can anyone help me solve this issue?