Shop not opening for player

I recently played a ranked match with player "mmPumpkenpie" who was unable to open the shop to purchase items. He was playing Fizz and kept logging in and out to fix the issue, which was never resolved. He stated that the problem had never occurred before now, so I can only guess it was something to do with the recent patch.

As frustrating as ranked matches can be for various reasons, this unfortunate reality is definitely a problem with hard and fast solutions. Thank you for reading.