I've noticed that too in other comics. But maybe it's a publishing thing. As in, they have N-chapters to tell the main story and if it does well enough, it gets approved for the "extras."
Plot-wise though, it's jarring to have just hit the climax and have only a chapter for the resolution. Here, we have a mini-climax in waiting for the prince to wake up. Because it's a love story, it could be argued that was the real climax over capturing the doctor, which then puts the climax at the very end with no resolution. The storylines that do well with the climax at the very end are ones that need an open ending, like a thriller. But romance needs the happy or bittersweet ending; having no time for resolution defeats the purpose of the genre.
I agree, it totally could be a publishing thing.
It definitely does depend on the story, here it felt off
It always confuses me when authors do extras/side stories that are just a complete continuation of the main story. It makes no sense :L
Extras should be like a POV change or a time jump or perhaps an AU.
This will just be an additional 20+ chapters of main story called something else ahahah