Shaco Clone Became AI?

Sorry I don't have a pic for this, but me and 4 friends played some One For All just now, and we chose Shaco. So I started to build a tank Shaco and used my ult in the jungle. After the timer ran out, the clone exploded and killed the mobs, but instead of disappearing, it became the same color as me and became an AI. It teleported to me when I recalled, and then followed me and auto-attacked things just like Tibbers. After they killed him, he had a death animation and for every ult I used after that, the same thing happened. My friends couldn't tell the difference between the clone and me, since we both had the nametag above us. Has this happened to anyone before?