Now that you point it out I kinda see it, but personaly I think the problem might be deadlines rather then this. It seems like series will be finishing soon so the deadlines might be a bit more tight as the story reaches its climax.
It could be also the problem after not drawing them for a while the artist might have fallen out of shape or smh, but personally I think deadlines are a bit more reasonable explenation

Doesn’t feel like the drawing quality in ch 77 dropped drastically ??? I see no one talking about it in the comments, but it seems like the author is struggling to draw them as adults again, it’s a bit unsettling, idk, anyone who feel the same?