atlas doesn't check if a relay's family members also list that relay in their family
(sorry, english isn't my mother tongue, so please excuse my writing)
As said in title, atlas isn't checking if all family members list themselves, so it leads to some ambiguous results, showing relay being part of the same family when it's not the case.
Below a copy/paste from the IRC (nicknames are anonymized as I didn't ask permission to paste the log)
< mickael> Hello, it seems someone is hijacking my family members, what can be done against that? I mean: a node pretends to be part of my family but it's wrong. I'm running one single middle node, nothing else. < nick1> it doesn't matter. < nick1> two nodes are only considered a family if they list each other. < mickael> Ok, so even if atlas tells we're part of the same family, there is no need to worry ? < nick1> probably correct. < nick2> sounds like an atlas bug < nick3> and even if nodes are in same family, I do not see any harm in it < mickael> nick1: thanks, nick2: do you want me to fill a bug report ? < nick4> oh in theory there is harm if you ask me, you would be able to make the tor network not use the two nodes in a circuit, no? < nick2> mickael: that could be helpful! I don't maintain atlas, so I can't guarantee much, but it is probably a good idea.