@SpookFromMR
As
@akselbuch already explained it. That is essentially "sniping" a manga from another translation group.
The foundation of that is this:
When a translation group starts translating a manga they usually do not know if that manga will be liked and hence they do not know how many readers there will be.
They start from 0 and build up a fanbase of readers for that manga.
As such translation groups usually respect that and do not translate chapters of a manga another group is translating.
There are only 3 exceptions as to why a group would actually translate a manga already taken by another group.
1.) The current group has disbanded or announced to drop the manga or did not translate any chapter for a long time even though there have been raw chapters left to translate - long time - maybe 6 months or more.
2.) The translator himself/herself of the manga switches to another translation group and takes the manga with him as it is his project.
3.) The current group makes horrible translations and another fan of that story cannot bear to have it translated so bad. Hence he/she starts translating that manga, too. - But in this case they usually start from the beginning of the manga because they want to correct the bad translation after all.
4.) The current group translates the manga (far) slower than the author actually releases new chapters - e.g.: Translation group: 1 chapter / 2months - Author: 1 new chapter weekly or monthly.
In this case it the current group usually looks for translators first or for joint translation with another group.
But in case that does not work out and the untranslated new chapters stack up massively there might be another group starting to translate the chapters to catch up to the raws.
Sometimes this then ends up with the new group taking over, sometimes the original group starts to speed up their translations and takes the manga back and sometimes the 2 groups start alternating between releases or do chapters together.
In these 4 cases another it is usually accepted if a new group translates a manga that was formerly translated by another group and as such are mostly NOT considered "sniping".
Unfortunately there are also cases where a translation group sees that a certain manga is popular and then translate a new chapter of it in order to get the readers to visit their website.
So these groups try to "snipe" manga for the purpose of getting more traffic to their on homepage.
They do not think of the readers, they do not do it to share the joy of reading that story and they do not respect the other groups.
They do it solely for the traffic and as such think of the readers as something that brings them money from advertising on their homepage or from donations.
These kind of groups are considered to "snipe" the manga from other groups.