I was recently playing with the Dark Warlock deck to complete quests and some achievements. Wallow is a card that acquires all the Dark Gifts you collect in the game (whether they are in your hand or not).
The bug was that my Wallow (which was in my hand) returned to the deck after gaining the Sweet Dreams buff (this returns my minion to the top of the deck and gives it +4/5). Upon returning to my hand, it lost its buffs (the Dark Gifts) (for clarification, I had several buffs: charge, +2/2 elusive, cost reduction, windfury and divine shield, etc and upon returning, I only had the +4/5 buff). Luckily, I didn’t lose the game, but it’s important to note that this is a bad card interaction or correct the bug.