Particle Effects fail to show in arena

[Cedarbridge]

Within the last couple days, none of the particle effects for my opponents have been appearing.

This includes

 

All summoner spell projectiles and floor effects like Doom n Bloom

All FM spells including aoe effects like meteor shower

Destroyer red spin effects and stone shield

Most Warlock projectiles including many ground-based aoes.

Assassin aoes and projectiles including landmines.

 

This has made the arena nearly unplayable.  This does not occur outside of the arena and none of my graphics settings were changed between the time when the effects appeared normally and when they stopped appearing.  This change did not occur at the time of a major or minor patch but rather started in the afternoon after normal play in the morning.