Aatrox invisible?

In my previous game, I was playing as Thresh support. On my team, we had me, Lucian , Yi , Rengar , and Kayle . On the other team, there was Aatrox , Kha'Zix , Lucian , Mordekaiser , and Talon . At one point during the game, Aatrox had just killed Rengar and he literally disappeared. Thinking it was fog of war, I went to midlane and got murdered by an invisible Aatrox. I could see the blood from his auto attacks and the ability where he slows you, but I could not see Aatrox on screen or on the minimap. After talking to him after game, he said he had no idea why he disappeared and I decided to report it as a bug. Has this happened to anyone else?