Why region detector doesn't work in game?[UNANSWERED]

How do i convert this to FE? I got a brick inside the model that i could drag, it's supposed to be the main detector of parts so when a player placed the model on a area where there is parts it will not allow it.

This is the brick detector script.

_G.detected = nil 
while wait() do

	local d = script.Parent
	local pos = d.Position
	local size = d.Size/2
	local reg = Region3.new(pos - size, pos + size)
	local p = script.Parent.Parent
	local ignore = {workspace.Baseplate,d,p}
	local n = workspace:FindPartsInRegion3WithIgnoreList(reg,ignore,100)
	if #n <= 0 then
		
		_G.detected = false
	else
		
	
	_G.detected = true 
	_G.down = true
		end
	end

Then on a player starterpack i got localscript for the main dragging, this is just part of it where assuming a player is dragging the model and released the button, we know that the brick detector will set detected to true if there is part so it'll not allow it, if detected is true then model will remain as mouse target.

mouse.Button1Up:connect(function()

	pcall(function()
	if (player.Character.Torso.Position - mouse.Target.Position).magnitude >= 100 or _G.detected == true then
	_G.down = true
	_G.target = mouse.Target.Parent

	script.Parent.Parent.PlayerGui.Warning.Enabled = true
	_G.selectionBox = Instance.new("SelectionBox")
_G.selectionBox.Adornee = mouse.Target.Parent
_G.selectionBox.Color3 = Color3.fromRGB(255,0,0)

_G.selectionBox.Parent = camera
	
	else

	_G.selectionBox.Adornee = nil

	_G.selectionBox.Parent = nil
	mouse.TargetFilter = nil
	_G.down = false
	_G.target = nil
	script.Parent.Parent.PlayerGui.Warning.Enabled = false
	_G.selectionBox.Color3 = nil

	end
	
end)	
end)

THE PROBLEM

the region detector doesn't work in-game only on studio. I can't think of any reason why maybe converting the detector script to F.E will fix but i don't know how..