Warwick Ult not Stopped by CC while it starts [GAMEPLAY]

While playing against Warwick, if he gets cc'd while he starts his ultimate it does not stop or prevent the crowd control of his ultimate. While playing both Ahri and Sejuani he has ulted into charms and sejuani ult and not been cc'd out of his ult. This happened when he ulted me while the charm was between me and him. This also happened when i sejuani ulted and he ulted onto a 3rd party character and still absorbed my ult without being cc'd. Steps:

1. have ww ult up
2. approach a champ with a skill shot hard cc (ahri, sejuani, xerath perhaps?)
3. shoot the skill shot between the both of you and then ww ult while it is flying at you
4. ww ult shil happens despite the cc thing being on him. This bug is really disappointing and has ruined some games for me when playing champs that try to cc ww as he approaches me. This has happened 100% of the time in game for me but i have no tried it in a custom.