Gameplay, ARAM, can't move within 30s of loading

Each time my ARAM game loads, I spend a few seconds purchasing items and leveling up abilities and moving around, but the game reaches a point where I can't move or click or do anything. I end up exiting the game and reloading, and the problem is gone. This gives the other team an early advantage in setup because of the time I need to reconnect to make sure things are working well.

Often, a few items that I purchased are not in my inventory and the levels that I clicked to level up are not there.

This bug sometimes doesn't happen during the first game I load after restarting the client, but it recurs every game after the first. This bug does not seem to affect summoner's rift.

Anyone else had this issue?