I've had a bit of time to look into these, no major fixes though just yet. I thought I fixed AniviaQ but then broke it again xD
For Anivia, IIRC it's a port of an old INT script so there's a lot to be improved on; recode/rework or maybe just a better way to Missile & Object detection/tracking/updating I want to look into.
Q2 currently relies on checking per CastQ() target if they are in Q2 radius @ GameObject.pos (works fine for R that doesn't move).
Not great for moving object, especially with the delay that Game.Missile()/Game.Object() have with anticheat measures + updating the GameObject.pos accordingly need improvement.
delays of ~ 25-100ms sometimes
For Dianna, But I think I know what you mean and have idea's for Dianna.
The Q pred is as a linear skillshot so there's some wonk. It could probably use some custom Arc predication, or use premium pred version of it might work.
Also could use the Vector behind target trick with Anivia W, Morde E, Trundle E.
no updates to push just yet.