- The first player lays down a draw 4 card.
- The second player draws 4 cards.
- The third player lays down a draw 4 card as well.
Does that mean the second player puts back their 4 cards. While the fourth player has to draw 8 cards?
Does that mean the second player puts back their 4 cards. While the fourth player has to draw 8 cards?
No.
The first player's action caused the second player to draw four cards and skip their normal turn; there is nothing in the rules which can cause that to be "undone". The third player's turn then proceeds as normal.
It may be worth noting here that "stacking" Draw 2 or Draw 4 cards is not part of the official rules even if it is a common house rule.