Fatigue in tavern brawl

When the opponent is forced to draw cards too fast in this week’s tavern brawl they sometimes fatigue instead of having their deck replenished.
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Using this deck, multiple research project casts will fatigue the opponent.

Same thing happens to me.

It’s not just with Research Project. You could do it your self if you draw too many cards.

Like if you have 7 northshire clarics that are all injured and you cast holy nova. Ive seen a priest kill them selves from it.

It’s not about drawing too fast, in fact. If cards that are to be drawn are burned instead, i.e. the hand of the drawing player is full, then deck is not replenishing itself automatically. So, if my opponent has 8 cards and 3 cards in the deck, and I play 2 research projects - or, likewise, 2 coldlight oracles - then they draw 2 cards normally, third get burned, then deck becomes empty and fourth card that they try to draw is fatigue card. Moreover, if I play another research project same turn, they get 2 more fatigue cards. Although if their hand doesn’t get overflowed, deck replenishes itself normally and no fatigue damage is dealt.