[Sion] - can be taunted out of his ult
If Sion is channeling his ult and a nearby Shen/Rammus/Galio/other taunts him while he is running, he will immediately stop and his ult will go on cooldown. According to his ult text he should be immune to all crowd control effects.
Steps: 1. Select Sion 2. Level up R 3. Ult past an enemy who taunts you 4. Notice that the ult is cancelled
Thanks for your time, I hope this can be fixed!
- xZelmecx