Seen this a lot since release (first game I ever played had it too). I’m not sure if it’s a logged issue or not, but the skill/ability effects and anything else that gives a burst of light/glow starts cause flashes and other visual distortions on the screen. It can be seen during the character selection screen as a monster with things like the Wraith’s particles or Goliath’s breath. The issue persists from then on, until the game is closed down.
(It’s not a v good video of it, but you can see it within the first 30-40 seconds)