HIDDEN PANTHEON ULT

Um Soo.... This has already happened mutiple or maybe all the time when I play a game against a Pantheon. His ult gets hidden (No I see a part of it...) in the bot lane and top lane of Summoner's Rift. If he ults between in the top lane and top river or bot lane and the bot river half of it gets hidden. Can anyone tell me about this if it is a bug or just me??!?!!?!?