Camille ult bug? Or expected behaviour?

Is Camille's ult supposed to interrupt abilities that are being channeled? If so, which effects exactly interrupt a channeling? Also, can you guys on Riot make some kind of effect-status message like "interrupted" when an channeling is interrupted? Say, for example, a , or ult, or when summoning Shelly. If not, please take a look at Nunu's ult when being ulted by Camille. I was recently playing a game where, every time I was ulting, she ulted me and my channeling was cancelled. I don't know if it is an expected behavior or not. Cheers!