In this game: https://18xx.games/game/199400
Action: https://18xx.games/game/199400?action=827

TR has just bought the 5 train, dropping the train limit to 2/3. Both TR and BK are over the train limit and need to discard. The interface only offers them the option of discarding the 2G trains, but BK has 4 trains and only 1 2G, it needs to discard another train but that option is not provided.

Even if BK discards the 2G, the button stays there and you can click it infinitely to keep discarding a non-existent 2G train. This is blocking the game from progressing

Browser: Chrome: 135.0.7049.96