Instance:SubtractAsync() does not always allow a player to walk through the union

I want to be able to create a hole in any part and to be able to actually walkthrough or stand in that hole, making a much larger hole allowed me to go in the baseplate, however for the other part, I scaled it down by a lot.
Visual example:

(file size exceeds max)

source goes roughly as follows:

			local part = Instance.new("Part")
			part.Size = Vector3.new(6,6,6)
			part.Name = "SUB45673"
			part.Anchored = true
			part.CanCollide = false
			part.Position = pos
			--part.Orientation = Vector3.new(math.random(-90,90),math.random(-90,90),math.random(-90,90))
			part.Parent = workspace
			part.Transparency = 1
			local region = Region3.new(part.Position - (part.Size/2),part.Position + (part.Size/2))
			for _,Part in pairs(workspace:FindPartsInRegion3(region)) do
				if Part.Name ~= "SUB45673" then
					local u = Part:SubtractAsync({part:Clone()},Enum.CollisionFidelity.PreciseConvexDecomposition, Enum.RenderFidelity.Precise)
					u.Parent = workspace
					Part:Destroy()
				end
				
			end
			part:Destroy()

It is a bit messy; however, it works to an extent.