There is a "rare" bug playing Katarina that happened to me yesterday and also at the next game to my girlfriend. It also happened today to my midlaner Katarina while i was playing Jayce. This bug makes you unable to use your Q or R skills and also to use the Recall. After several reconnections and trying different ways to solve it, my girlfriend managed to discover that the solution is dying with her, but it is not always a option.
The solution that i suggest is disable her until it get solved.
Thank you for reading.