Personally, I don’t see why either group should be reprimanded on so-called “etiquette”. In the Novel Translation community, it is not considered Sniping if the new/second group starts from chapter 1; which both groups here have done.
Perhaps I’m just an old timer, but this really should be considered as friendly competition rather than “HOW DARE YOU UPLOAD 1 HOUR LATER!?”. Even moreso in this case where neither translation/post-editing is perfect, said competition actually benefits the readers with different interpretations of the text.
And let me add an aside. If “speedrunning” the scans is your primary objective and the quality of the work suffers then you really should stop and reconsider your professionalism. SSUS clearly dropped the ball in this regard with subsequent releases (I’m looking at you, chapter 5). Haevn also got a bit lazy with typesetting, but that is understandable given the volume of chapters. Haevn also had the decency to translate sound effects, which SSUS completely gave up on trying. So for those saying Haevn is just “wasting their effort” then you clearly did not read closely enough to see the additional quality they added to their scans.