*Facepalm*
So this is how Tumblr, MAL and Reddit looks like eh ...
Now for the record, /a/ is not a group and this been translated in /a/ for quite a while, they havent typeset it on raws because that is work and nobody wanted to do it until eventually they got tired of the gap and decided to poke #dropout to see if they picked up the pace, in fact lets talk about #dropout for a bit ... this series was originally monthly so 1 chapter release per month was fine but at one point it switched to a weekly format but #dropout pretty much keep 1 chapter per month meaning every time they released a chapter, they would further 3-4 away and this was why there was already a 48 chapter gap that was why /a/ decided to poke then since the anime wasnt making then pick up the pace so ... they did that.
And /a/nonymous is just the name used for releases from /a/, it might be the same persons but chances are they are not across the many series /a/ have worked over the years, the fact its not usual for then to have credit pages (and in this case, they were made as a joke).