What's the drama in this arc? I thought Katakura is just taking a break thanks to Yuu's bento.
"at the time I didn't think anything of it" is a very loaded statement that strongly implies there's more going on here than her just taking an innocent break from the column. It's pretty much "There's a lot more going on here than is seen at first glance."
Like if she showed up at the restaurant and there was a closed sign on the outside and the narrator box said "at the time I didn't think anything of it", the expectation would be something like she at first thinks he's just sick, then it remains closed for a solid week and nobody can find where Yuu is and then they find out that he fled the country because he's being hunted by the Yakuza or something dramatic.
Maybe it doesn't go
super dramatic but this is not just going to be her taking a week or month or whatever off from her column. It's going to be that something else is going on and likely that through the bento shop she gets caught up in it just like she did with the owner's son and the backstory about the owner's daughter/his wife and her dream and everything else that was so drama-laden last time around.