Apologies for the long post, but just wanted to mention something.
Just a small thing I noticed going back and looking at the previous chapters to get a sense of how Aya couldn't possibly know about this, or if she's just a terrible person. I remembered them talking about Ta-kun a while back and originally thought there's no way Aya was such a shitty person to give love advice to her friend while knowing that she was after her ex. In chapter 11, during the group dm of the friends, they're explicitly talking about him, and I noticed something that in hindsight was mistranslated.
It's very difficult to directly translate, but Yuka's (the blonde) text bubble (#5 from the top) says 「そうそう!
夕くんと
ひかりんだけに、”夕陽”をバックにさ~」or romanized "Sousou!
Yuukun to
Hikarin dake ni, "YuuHi" wo bakku ni sa~". The word for sunset 夕陽 (Yuuhi) is indeed a combination of the first syllable of their first names. In the Japanese text, the Yu and Hi are emphasized in Yuka's text message to show what she's saying. Hikari does indeed call him "Ta-kun", but in Japanese, without the ~ character, the name is read as "Yuukun".
Confused, Aya says 「ゆう?あれ?ターくんじゃなかったっけ?陽花梨の彼氏って」or "Yuu? Are? Ta-kun janakatta ke? Hikari no kareshi?". The translations of both bubbles are correct, but because this is the first time the story has called him "Yuukun" at all, it makes sense why the translator left it as "Ta-kun".
Thank you for sticking with me because
my point is that it seems (at least to me, having read both) that Aya up until this point did not know who Hikari's "boyfriend" was, and thought his name actually was "Ta-kun" like "Taiki" or "Takuto" or something like that that starts with "Ta", instead of either a reference to his last name (Takamura) or that the kanji for his name 夕 "Yuu" is nearly the exact same as the Katakana character for "Ta" タ.
This was a small hint that something was weird that seemed to slip past English readers, although Japanese readers got it. We didn't get the first instance of "Yuukun" until chapter 16.
Just wanted to mention this in case anyone went back and maybe got confused by this panel.