Orieux says the same, i.e. Fritz and Voltaire show up in Bayreuth together, and Voltaire stays there somewhat longer than planned while Fritz leaves. Much to Émilie's chargrin, since he'd promised her to remain only ten days in Berlin in totem, with no extra trips announced. (The passage I quoted in my Orieux write up follows, about why Voltaire was so charmed there, and Orieux wishing Émilie would have come with him since Germany would have treated her far better than Paris had done.)