Question: What happens if someone other than East, discards the first tile?

Answer: If a player mistakenly discards a tile thinking they are East, the player can take the tile back and the correct East can discard.  However, if a player other than East picks a tile and discards, the tiles are thrown in and the game restarted. 

Source:  Mah Jongg Made Easy 2024 page 14, bullet #9