If you keep Enochian up long enough (using Blizzard IV) that the cooldown comes back up and recast Enochian while it is still up, it refreshs Enochian like Blizzard IV meaning it refreshes it with the time minus 5. So if I last cast Blizzard IV and it was 15 seconds, recasting Enochian while it is still up at lets say 7 seconds refreshes it to 10 second and not to the full 30 seconds.

I hope this isn't intentional as it is a issue that could cause you to lose Enochian if you accidentally cast it while the buff is still up, at 10 seconds it your are not going to keep it up let alone get only 1 to 2 fire IV off and then you have the full cooldown almost to deal with.