No he doesn't. He's been given the ability to see kanji on his girlfriend's face that finally let him understand what she's feeling, because her expressions are fairly neutral. In this chapter, he runs into a genuinely funny problem that can only really work well in a language like Japanese: sometimes the kanji are really complicated characters that mean very specific things, and he has no idea what they mean. So, in order to figure out what she's feeling, he starts furiously trying to look them up. He's trying to understand her and respond to her feelings, but was sent into a flurry of searches to figure out what this character that he's never seen before is.
Your issue with him is that he didn't solve this immediately? I'm sorry, but that's, like... dumb. The whole point of this chapter was to introduce a potential wrinkle, have the audience laugh at the relatable attempts to solve it, and then show that by obsessing over these strange kanji that didn't even really hold significance, he was neglecting her. In his attempts to understand her, he neglected to pay attention to anything other than those kanji. If it was easy, the chapter wouldn't be funny nor would there be a chance for character growth.