Leopard Nidalee's spears are invisable

I just played the most frustrating game. A leopard nidalee stood outside of our base at and threw spears in... As soon as the spears passed through the base wall (the wall by the inhibitor turrets) the spear became invisible. I was killed several times and all I could hear was the spear hitting my character. I warded the outside of the base to confirm, I could see the spear leave her hand and start to enter the base but as soon as it passed the base threshold it became completely invisible.