In game bug When using Yeti's, you gain abilities from Fang and Fur, sometimes these abilities randomly go on cooldown, or just won't work. It seems a little bit inconsistant, but I have a feeling it may have something to do with champions dying and then a new champion being deployed. I don't think its adding/preserving cooldown correctly in there.
I noted this bug. If you happen to narrow it down further be sure to post here because there is a link to this thread tied to the note.