OMG yes. It is really frustrating and annoying and makes an already struggling Soraka suffer even more. I'm not sure this is not addressed.
Here is my example:
I silence Cait as she is flying backwards from E. As many caits like to do they cast E and then Q for double ability damage. So, I think hah she is silenced she won't be able to do it. But even though she is silenced and the silence notifier is clearly on her she is able to finish her E, acceptable, but then cast Q basically ignoring the silence.
Garbage.