Nocturne ult makes wards revealed by sweeper invisible

Played a game where I used oracle's lens at the same time the enemy nocturne used his ultimate. I saw the static looking effect from sweeper that indicated a ward was disabled but could not see the ward itself despite being right next to it because of the nocturne ult. When the ult ended the ward was revealed like normal, making it pretty clear that the ult is what caused the bug.