After playing on my Psyker I have noticed that a warp anomaly, the purple warp tornado that chases you, is spewing out large white flickering clouds. This also happens when one of the Khorne commander mobs (Herald of Khorne, I think) does it's aoe attack. These clouds are large and noticeable, and seem very much out of place, obscuring the effects underneath.
I have also noticed that certain weapon cause significant performance issues the more they're used, the game will slow down quite a lot, and if used in larger fights, it will slow down to a crawl. So far, I've only noticed this with the Radium rifle alpha/beta and the Wyrdvane staff. The game performance is already kind of poor as it is, but these weapons make it unplayable, and as such, I've been avoiding them.
I'm playing on a normal PS4