If he got to know Yurie's family name from list or name tag, and so on, it's not a so unusual thing.
As your knowing, "一橋" kanji has two readings. And he dos't decided reading only by seeing "一橋" kanji.

However in actlly, he got to know her family name from her tarking.
It's pretty weird that he hears "Hitotsubasi" reading, although he memorizes as "Ichihashi".
Under conversation, Normal Japanese people also memorizes one'name as sound preferentially than kanji character. (As like English sperker memorizes one'name as sound preferentially than spelling.)
I think this confusion is expression of his unique characteristic and he isn't interested in her at chapter#1 yet.

Because I'm a Japanese who can't speak English, this sentence is may be strange. But It is glad if my text make sense :)

>>1644
Thanks for taking your time to explain! ヽ(´ー｀)ノ

yeah... it works for me too.. thanks for the explanation

Thanks! ^_^ Kamichu is looking super cute so far, i really love the smoothness in the animation, and the easy going story. I have high hopes for this one! :)

I agree with >>1644 in that

>this confusion is expression of his unique characteristic

but I disagree on the subject of his interest.

He remembered her name. Even if only the kanji version. This, I gather, is unusual for him. I think he *is* interested.

>>1644

Thank you for your explanation! I enjoyed it and feel enlightened!

What is this anime?

Kamichu!