[GAMEPLAY] In game HUD did not display properly. Blurred and blocky appearance

When spectating a game, I observed that the in game HUD failed to display correctly, appearing as if the elements were images that only partially loaded. The HUD areas and the icons contained in it were blurry and blocky but not the ability or spell icons or the text. The blurred element were HUD back plates, player's stat icons, champion portrait borders, ability level up buttons, player's health and mana bars, icons in the KDA/CS/game time area, the buttons for Alert Ping, Champion Info, Item Shop, Camera Setting and Option Screen. Attached is a picture of the elements that were distorted.

This persisted through the rest of the match. I have no leads as to what could have caused this error.