Lux gamebreaking bugs

All in the same game. I was the Lux.

1- Enemy Nidalee dives me: with shield from w and barrier I survive her w and q in cougar form, the she does her E. It should have killed me but it didn't do any damage. We both don't understand wtf happened.

2- I catch enemy Cassiopeia with my q and use my ulti to kill her. My ulti takes her but she doesn't receive any damage so she walks away. Following "wtf" from both of us in chat.

3- I catch enemy Cassiopeia with my q, but I do that too near her so she uses her poison and begin the E spam. I use my ulti, hoping my animation will finish before I die for her Es. In that same exact moment she uses her ulti, catching me while I am mid-air charging my laser... but I don't get interrupted, finish my animation and kill her.When she is already dead on the floor I get petrified and receive the stun ( ??? ).