Quote Originally Posted by Naizakane View Post
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?
Players without tenpai have to pay out points to players with tenpai when the game ends in a draw, that's why. Houtei is a risk but that's their own decision to make. I'm not saying it should be changed if that goes against every other ruleset; but it's not hard to see the motivation behind wanting to do so