While not really a bug, I think this needs some clarification. The ability text on Abominable reads: "This unit has Arctic and deals +1 DMG to Scented units for each friendly Yeti. When activated, the closest real enemy unit is Scented. If that unit is stealthed, it becomes Frightened for 2 turns." Firstly, it only counts all other yetis than the one doing the damage. So I think the wording there is wrong. Secondly, the bonus DMG is only applied on basic attacks. This does not apply to some abilities that state they are basic attacks though. Attacks that don't gain bonus DMG (that I have tested): Knockback, Cleave, Charge, Snowball, Howling Attack, Pummel, Ice Carved Greaves, Frost Cone (from Yetihide Cloak) and Defensive Strike (from Iceguard Bracers). Since the ability Abominable says that the champ deals +1 DMG to Scented units, one would assume it's on at least most "attack" abilities that do DMG. Lastly is says it effects enemy "units", but currently it only works on champions. Relics are not scented.
