É um erro.
No site antigo da JKR afirma;
Interviewer : At the end of 'Goblet of Fire', in which order should Harry's parents have come out of the wand?
JKR : Lily first, then James. That’s how it appears in my original manuscript but we were under enormous pressure to edit it very fast and my American editor thought that was the wrong way around, and he is so good at catching small errors I changed it without thinking, then realised it had been right in the first place. We were all very sleep-deprived at the time.
Isso foi corrigido em edições posteriores (assim como alguns textos ligeiramente alterados foram adicionados).
Na minha versão do e-livro dos EUA (2013), afirma claramente:
And now another head was emerging from the tip of Voldemort’s wand … and Harry knew when he saw it who it would be … he knew, as though he had expected it from the moment when Cedric had appeared from the wand … knew, because the woman appearing was the one he’d thought of more than any other tonight … The smoky shadow of a young woman with long hair fell to the ground as Bertha had done, straightened up, and looked at him … and Harry, his arms shaking madly now, looked back into the ghostly face of his mother.
‘Your father’s coming …’ she said quietly. ‘He wants to see you … it will be all right … hold on …’ And he came … first his head, then his body … tall and untidy-haired like Harry, the smoky, shadowy form of James Potter blossomed from the end of Voldemort’s wand, fell to the ground, and straightened like his wife.