I was reading on discord they want status to represent the status of the manga in Japan, not the status of the scanlation. Makes sense given mangadex is hosting many languages, so it may be complete in one but not another language.
@Jpwong
That's actually misleading as hell.
Given that the site appears to be english focused, it would make more sense for the status to be representative of the english scanlation. Batoto also did it that way.
I wish thus would update faster; this is one of my favorite series and would even go as far as to say it deserves an anime adaption and I think the japanese studio AIC should do it since they did Date A Live, my favorite anime
"Pub. status: Completed" As in, publishing status in the country of origin. In this context if there are only three chapters left, then yes, it is completed. The indicator for a particular language's scanlation is whether or not there's a chapter with an "end" slapped onto it on the chapter listing.