It's a Mangadex platform quirk. The original translator dropped the series, it sat for six months, and I picked it up and translated everything up to current. However, the last four chapters the original translator did weren't tagged with volume numbers because they were being done on a weekly basis as they were released. Mangadex sorts anything with "No Volume" at the top of the list, because it's assumed to be part of the latest batch of serialized chapters that haven't been published in volume form yet. So it creates a gap from Ch54 (volume 7) to Ch59 (the first chapter properly tagged as Volume 8), and then another discontinuity jumping from Ch68 (last one in Volume 9, the most recently released volume) to Ch55 (the oldest chapter that doesn't have an assigned volume number.
Unfortunately, the only people who can fix this are either the original translator (and no one I've talked to knows how to get in touch with him) or Mangadex staff.