Any time you see a series get wiped here, it's usually because the scanlation group requested it. Often when you see a series "ressurected" in small amounts, it's been grabbed by a new group.
@bufu12 Meraki got a C&D and dropped it where Jamini's picked it up. After that, the MD fiasco happened so a lot of groups jumped ship from MD and since MD's goal has always been to cater to scanlators they removed their chapters per their request. Solo Leveling Scans are here to fill the gap that Meraki and Jamini's left by leaving.
@Deathhappens Short version: Some older scanlating groups threw a bitch-fit because they saw some statements about what "going legit" for Mangadex might entail in the far future. They interpreted this as Mangadex intending to backstab them, pulled their respective scanlations, openly declared their intentions to drive Mangadex into destruction, fucked around for a couple of days, then left the site altogether.
Obviously, their behavior during this whole affair pissed me off, so I am biased in favor of Mangadex. Especially since some of the scanlation groups have sold out entirely to corporate entities and now allow various forms of corporate data-collection on their sites. Leviatan Scans now has Google syndication plugins, for example.