When he told Voldemort that the Order had laid a false trail about moving Harry Snape?

When Snape informs Voldemort that the Order had laid a false trail about moving Harry, he is actually lying in order to protect Harry and ensure his safety. Snape's true allegiance lies with Dumbledore and the Order of the Phoenix, and he is not revealing their true plans to Voldemort. This deception ultimately helps in keeping Harry out of harm's way.