Varför säger Hermione "Glöm det" om Hagrids mamma när hon inte kunde veta innan hon var död?

Vi hör Hagrid om sin familj för första gången i kapitel 23 (Yule Ball).

“It was my mother,” said Hagrid quietly. “She was one o’ the las’ ones in Britain. ’Course, I can’ remember her too well . . . she left, see. When I was abou’ three. She wasn’ really the maternal sort. Well . . . it’s not in their natures, is it? Dunno what happened to her . . . might be dead fer all I know. . . .”

Och så får vi lite mer information från Rita Skeeter i nästa kapitel (Rita Skeeter's Scoop)

His mother, we can exclusively reveal, is none other than the giantess Fridwulfa, whose whereabouts are currently unknown. . . . While many of the giants who served He-Who-Must-Not-Be-Named were killed by Aurors working against the Dark Side, Fridwulfa was not among them. It is possible she escaped to one of the giant communities still existing in foreign mountain ranges.

Så vi vet att varken Hagrid eller Harry, Ron eller Hermione känner till Hagrids mammas öde. Och sedan i Order of Phoenix, kapitel 20 (Hagrid's Tale) säger Hermione

“Hagrid?” said Hermione quietly after a while. “Mmm?” “Did you . . . was there any sign of . . . did you hear anything about your . . . your . . . mother while you were there?”

Naturligtvis efter att ha hört vart han hade gått var hon nyfiken på att han lyckades träffa sin mamma. Och sedan omedelbart efter det säger hon:

Hagrid’s unobscured eye rested upon her, and Hermione looked rather scared. “I’m sorry . . . I . . . forget it —” “Dead,” Hagrid grunted. “Died years ago. They told me.” “Oh . . . I’m . . . I’m really sorry,” said Hermione in a very small voice.

Hon säger "Jag glömde". Men när lärde hon sig om Hagrids mor när den till den fjärde boken var osäker på om hon är död eller levande?