Melee Minion Ignores Everything

Not sure if anyone else has had this but in 4 of my games over the last two days I've always seen at least one melee minion just ignore other minions and champions and just keep walking until he died to turret or other minions. It's weird because he walked into the line of minions that were coming and created a sort of unintentional freeze for a bit. Anyone else had this?