Rascal Does Not Dream of Logical Witch (Manga) by Hajime Kamoshida
One night, Sakuta happens to see his friend Futaba entering a net cafe...while he's on the phone with ANOTHER Futaba?! It's another case of adolescence syndrome-and as this other version of Futaba very logically points out that it's likely dangerous for doppelgangers to meet for one reason or another, he'd probably better let her hide at his place...?