I was doing a 1v1 in The Proving Grounds, and minions were attacking The Nexus. Not long after they started, my inhibitor respawned. Instead of falling back to go after the inhibitor, all of the minions walked around the nexus (Now closer to my spawning pool, but facing away from it.) and remained still. If I get the time tonight, I will try and recreate this, as well as testing what would happen if the inhibitor was destroyed while they were still standing still.