这个问题可能是由于缓存不正确或已过期所导致的。尝试添加以下代码以便清除缓存：

GoogleApiClient mGoogleApiClient = new GoogleApiClient.Builder(context)
        .addApi(Games.API)
        .addScope(Games.SCOPE_GAMES)
        .setAccountName(accountName)
        .build();

mGoogleApiClient.connect();

Games.Achievements.load(mGoogleApiClient, false).setResultCallback(new ResultCallback() {
    @Override
    public void onResult(@NonNull Achievements.LoadAchievementsResult loadAchievementsResult) {
        if (loadAchievementsResult.getStatus().getStatusCode() == GamesStatusCodes.STATUS_OK) {
            AchievementBuffer achievementBuffer = loadAchievementsResult.getAchievements();
            for (Achievement achievement : achievementBuffer) {
                Games.Achievements.reveal(mGoogleApiClient, achievement.getAchievementId());
            }
        }
    }
});

这段代码会重新加载并显示所有Play Games成就。如果成就依然无法显示，建议检查你的网络连接和登录状态。