Why didn't Leaf noticed that Kara might have a former leaf shinobi

[Pulkit singh3]

Let me explain-
Katasuke was put into genjutsu by a Kara member and leaf knows that, obviously Katasuke was in the village when this happened and in latest chapter of Boruto Kashin koji said it clearly that if an outsider step into the village they will know it instantly but that didn't happen because the guy who put Katasuke into genjutsu is a former leaf shinobi.

Why can't they figure out such a simple thing

 

[Reboryushon]

Maybe it will be revealed, maybe it will forever stay a plothole but we know KK is able to enter the village because somehow he was from the village or his DNA is registered in the defense barrier.