Shaco boxes not sweeping

I don't have a screenshot or anything, but throughout my game, my oracle lens wasn't revealing or disabling Shaco's boxes. I made sure it wasn't because they had already been revealed or if I had swept them too early. I waited for the box to disappear and about 30 seconds later swept it. It did not reveal it nor did it disable it as I then moved on top of it to activate the box. I was playing Shen. The recap of the game in question can be seen here: http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/1991004441/32247384