Jarvan IV ult blocks minions

It began after I ulted as Jarvan IV and I died right after I ulted. The ring that the ult creates disappears, but on the minimap, there was a circle of minions. I remembered how one of Jayce's abilities was programmed as a wall of minions, so I thought the same applied here. The issue was that the circle of minions blocked the enemy minions for the rest of the game.

I have screenshots, but I can't upload them here. If there's an admin that's willing to look into it for me, I can email the screenshot or something like that.