Strange thing about Zhao Min in HSDS...

[Laviathan]

In HSDS Chapter 23, when seeing Zhang Wuji for the first time at Green Willow Mansion, Zhao Min mentioned that Zhang's father was nicknamed "Iron Brush Silver Hook" and was a great callgrapher, so it seems that she knew about Wuji's father Zhang Cuishan. But in the next chapter, she clearly didn't knew Zhang Sanfeng was Wuji's grandmaster, nor did she knew Wuji had anything to do with Wudang.

Is it just me, or is this a Jin Yong goof-up?

[HuangYushi]

Nah, not you.

It's either Jin Yong (a goof-up like you said) ... or Zhao Min trying to save herself some face after realising that she and her people were about to suffer another round of embarrassment in the hands of Zhang Wuji and the other leaders of the Ming Sect. She started off questioning Zhang Wuji in a soft/gentle voice [细声细气] before coming more aggressive and scolded Zhang Sanfeng and Yin Tianzheng. Quite stereotypical of young women who are used to getting their way, perhaps?

[Candide]

She was scolding ZSF and YTZ as two old farts scratching each other's back for teaching such a bright young man so I believe she was trying to save face. I agree with Huang Yushi, she's a young girl afterall and as we all know, they have no logical processor built-in... How many times have you had the "Yes I am! No you aren't! Yes I am! No you aren't!"^n argument with a chick?

[kyss of the sword]

wuji was quiet famous because of his parents and godfather, so after becoming the ming sect leader, when zhaomin wanted to find out about his background and relation with ming sect in order to impersonate him, one of her subordinates must have mentioned that he was white eagle's grandson and his father was 'iron brush silver hook' and a famous calligrapher but did not mention that ZCS was ZSF's disiple. so she made a goof at wudang.

[MisterM]

As has already been mentioned I think ZM was feeling stupid for not recognizing Wuji sooner and was trying to come up with excuses for herself.
I think it's not that she didn't know of Wuji's relation to Z3F, but that she never expected Wuji, who was the leader of the usually arrogant Ming sect and already considered the number 1 martial artist in the world by many, to act so humble in front of Z3F and she had previously been told that Wuji had not arrived at Wudang yet, so she unconciously dismissed the possibility of the "dirty boy" fighting in Z3Fs place beeing Wuji eventhough she should have recognized him. Then, feeling stupid for missing the obvious, she started the already mentioned "Yes you did!" trying to blame Wuji for her own mistakes as girls usually like to do, eventhough she wasn't making any sense at all... IIRC she also claimed that he had mistreated her when he got her to give him the antitode, and that's not true either...

[Laviathan]

But don't forget: Zhao Min was trying to frame the Ming Cult, and she herself used the identity of Zhang Wuji at Wudang to do so. If she knew about Wuji's background, why would she act this way? Please don't say it was to confuse Zhang Sanfeng, he clearly saw that she was a girl.