WARNING: This is a work in progress update. I'll remove this header when it's done, but for now just sit tight.
Edit: Still messing with junk.
The PBE has been updated!
Championship Riven particle fix went through
Fair warning: I'm not 100% sure if the following changes to Janna's particles were intentional or not. The ultimate graphic was previously seen as exclusive to Victorious Janna and Frost Queen Janna's particles have not been updated. This is just a guess though, good guy Riot could have just updated Janna's particles for the sake of updating them; the old Q was very rigid compared to this new one.
Janna had an update to both the build up and release particles of her Howling Gale ability.
Additionally, the particles of her ultimate were updated to match those we've previously seen on Victorious Janna in earlier PBE patches.
Here is a quick video showing off the two updated graphics since the pictures don't quite do them justice: