Aatrox ulti+Mariner's Vengeance bug on BB

I just played Aatrox in ARAM (BB) and I noticed that the passive of Mariner's Vengeance goes on cd if I use Aatrox's ulti first. The opposite thing also happened; the ulti went on cd as soon as the item's passive ended.

Had anyone else had this happen? I think it's worth looking into, for future comebacks of this mode/item/champion combination.