Board Thread:Theories and Speculation/@comment-31338621-20200901181802/@comment-32685487-20200928214809

Disregard that, Ao was only stating his eye(Byakugan) saw through the Genjutsu placed on the 4th, basically no Genjutsu can go unnoticed by him. Either way Obito's usage of the unnamed Genjutsu was basically retconned, and only used again in the Road to Ninja Movie. Otherwise the 4th War would have ended before it even began.