I might be misremembering things, but when Korisu was first getting introduced, wasn't it implied that there were some problems with her home life, like she was on her own FAR too often or her parents were different? Something about her mother, this chapter, feels off. Not in the sense that she's poorly written, but more in the "there's something going on there," way.
The only thing that note said is that she needed to buy dinner and some money that her mom left. While yes, she seem to be alone often, her mother seems to actually care about her which honestly is great, because while angst is good I really didn't want her mother to be a shitty person or at the very least leave her alone for a dumb reason