Actually they did drop the series earlier but have picked it again as an omnibus format. I don't think there's digital version of vol 15 that was contained in omnibus 5. But yeah, it's dark horse so it's better to have an alternative.
@s0larus They don't actually have a site nor do they share on discord. From what they've said, they use this time to check for errors and correct them. It's not technically locked. It's just they haven't actually "properly" finished working on the chapter.