Quote Originally Posted by Raionek View Post
Because that's how should it work normally. Player still should be able to make a call for the last tile even if it's not a ron. It seems to be a bug that ends the game immediately not allowing player to do that.
I have played riichi mahjong on four clients including FFXIV. Not a single one of them lets players call the last tile for anything that isn't ron. Tile calls on the last tile are limited to ron only. From riichi.wiki: "Finally, the last discard cannot be claimed for any open calls, even if needed to attain tenpai. The call on the last discard is limited for winning hands, by which houtei raoyui is rewarded."

Given this, the hand ending once the last tile is discarded, even if it's a tile you could call via pon/chi to attain tenpai, is not a bug, but intentional. Again, why would you want to set yourself up to be hit with houtei?