Both this and "Love is disgusting" ended in short order, suggesting simultaneous axe or something coming up in Usui's life.
Also the specific way they just came to an abrupt end, with Asako suddenly getting a callout from her sister and then going to meet her (abandoning the buildup), then Nagi saying "screw the plan I'll tell you now". It really feels like there was so much more of these stories to tell. That's how it goes sometimes, unfortunately.
In my opinion could be related to Usui Shio sensei work schedule, she seemed working non-stop since Crescent moon and doughnuts ended, initializing Trying out marriage with my female friend almost at the same time, then taking two consecutives series in the same magazine, that sounds like the kind of load of work why mangakas retire jajaja (hopefully not ofc, i want her to stay healthy and happy :)