“Wait until your father hears! Ron, I’m so proud of you, what wonderful news, you could end up Head Boy just like Bill and Percy, it’s the first step!…”—“Well, what will it be? We gave Percy an owl, but you’ve already got one, of course…” (Order of the Phoenix)
Why did Mrs Weasley just mention Percy if she is supposed to go ape every time anybody mentions him?
Contrast this with a couple of pages later:
She stopped dead, catching her breath with a frightened look at her
husband, whose expression was suddenly wooden.