Veiger invincible - ARAM

After taking down the first tower in ARAM, we noticed Veiger (opposite team) just standing still. So we attempted to attack him, but we were doing no damage.

At the start, he played normally until after his second death where he stopped attacking. His movements thereafter didn't resemble something that a normal player would do, he would slowly follow our minion wave, taking 0 damage.

I do not know how to replicate this bug, so here's all I can help with: -Abilities did no damage too, although we could still lifesteal off him. -He was not cc immune. -His 2 final items he had was and

I posted a recording.