No champions, minions, or shop in first 5 minutes of game

I just played a Flex 3v3 game where no champions spawned. I could chat, hear pings, and learn an ability, but couldn't purchase items or see any champions or minions. Riven on the other team convinced me that they had the problem too so I kept chatting to figure it out. Eventually I restarted the game and everything was back to normal. Except my team getting murdered and me going to lane 3 levels behind.

Anyways, a bit salty because it was a ranked game. Let me know if I can provide more info to fix this bug.